diff --git a/src/dump.cpp b/src/dump.cpp
index 2e6df77cd9..480bbe666c 100644
--- a/src/dump.cpp
+++ b/src/dump.cpp
@@ -150,19 +150,19 @@ Dump::Dump(LAMMPS *lmp, int /*narg*/, char **arg) : Pointers(lmp)
 
 Dump::~Dump()
 {
-  delete [] id;
-  delete [] style;
-  delete [] filename;
-  delete [] multiname;
+  delete[] id;
+  delete[] style;
+  delete[] filename;
+  delete[] multiname;
 
-  delete [] format;
-  delete [] format_default;
-  delete [] format_line_user;
-  delete [] format_float_user;
-  delete [] format_int_user;
-  delete [] format_bigint_user;
+  delete[] format;
+  delete[] format_default;
+  delete[] format_line_user;
+  delete[] format_float_user;
+  delete[] format_int_user;
+  delete[] format_bigint_user;
 
-  delete [] refresh;
+  delete[] refresh;
 
   // format_column_user is deallocated by child classes that use it
 
@@ -1019,7 +1019,7 @@ void Dump::balance()
   memory->destroy(tmp);
   memory->destroy(proc_offsets);
   memory->destroy(proc_new_offsets);
-  delete [] request;
+  delete[] request;
 }
 
 /* ----------------------------------------------------------------------
@@ -1059,7 +1059,7 @@ void Dump::modify_params(int narg, char **arg)
         if (strcmp(id,output->dump[idump]->id) == 0) break;
       int n;
       if (strstr(arg[iarg+1],"v_") == arg[iarg+1]) {
-        delete [] output->var_dump[idump];
+        delete[] output->var_dump[idump];
         output->var_dump[idump] = utils::strdup(&arg[iarg+1][2]);
         n = 0;
       } else {
@@ -1077,7 +1077,7 @@ void Dump::modify_params(int narg, char **arg)
         if (strcmp(id,output->dump[idump]->id) == 0) break;
       double delta;
       if (strstr(arg[iarg+1],"v_") == arg[iarg+1]) {
-        delete [] output->var_dump[idump];
+        delete[] output->var_dump[idump];
         output->var_dump[idump] = utils::strdup(&arg[iarg+1][2]);
         delta = 0.0;
       } else {
@@ -1107,7 +1107,7 @@ void Dump::modify_params(int narg, char **arg)
       MPI_Comm_free(&clustercomm);
       MPI_Comm_split(world,icluster,0,&clustercomm);
 
-      delete [] multiname;
+      delete[] multiname;
       char *ptr = strchr(filename,'%');
       *ptr = '\0';
       multiname = utils::strdup(fmt::format("{}{}{}", filename, icluster, ptr+1));
@@ -1124,14 +1124,38 @@ void Dump::modify_params(int narg, char **arg)
       flush_flag = utils::logical(FLERR,arg[iarg+1],false,lmp);
       iarg += 2;
 
+    } else if (strcmp(arg[iarg],"colname") == 0) {
+      if (iarg+2 > narg) error->all(FLERR,"Illegal dump_modify command");
+      if (strcmp(arg[iarg+1],"default") == 0) {
+        for (auto item : keyword_user) item.clear();
+        iarg += 2;
+      } else {
+        if (iarg+3 > narg) error->all(FLERR,"Illegal dump_modify command");
+        int icol = -1;
+        if (utils::is_integer(arg[iarg + 1])) {
+          icol = utils::inumeric(FLERR,arg[iarg + 1],false,lmp);
+          if (icol < 0) icol = keyword_user.size() + icol + 1;
+          icol--;
+        } else {
+          try {
+            icol = key2col.at(arg[iarg + 1]);
+          } catch (std::out_of_range &) {
+            icol = -1;
+          }
+        }
+        if ((icol < 0) || (icol >= (int)keyword_user.size()))
+          error->all(FLERR, "Illegal thermo_modify command");
+        keyword_user[icol] = arg[iarg+2];
+        iarg += 3;
+      }
     } else if (strcmp(arg[iarg],"format") == 0) {
       if (iarg+2 > narg) error->all(FLERR,"Illegal dump_modify command");
 
       if (strcmp(arg[iarg+1],"none") == 0) {
-        delete [] format_line_user;
-        delete [] format_int_user;
-        delete [] format_bigint_user;
-        delete [] format_float_user;
+        delete[] format_line_user;
+        delete[] format_int_user;
+        delete[] format_bigint_user;
+        delete[] format_float_user;
         format_line_user = nullptr;
         format_int_user = nullptr;
         format_bigint_user = nullptr;
@@ -1146,7 +1170,7 @@ void Dump::modify_params(int narg, char **arg)
       if (iarg+3 > narg) error->all(FLERR,"Illegal dump_modify command");
 
       if (strcmp(arg[iarg+1],"line") == 0) {
-        delete [] format_line_user;
+        delete[] format_line_user;
         format_line_user = utils::strdup(arg[iarg+2]);
         iarg += 3;
       } else {   // pass other format options to child classes
@@ -1204,7 +1228,7 @@ void Dump::modify_params(int narg, char **arg)
       MPI_Comm_free(&clustercomm);
       MPI_Comm_split(world,icluster,0,&clustercomm);
 
-      delete [] multiname;
+      delete[] multiname;
       char *ptr = strchr(filename,'%');
       *ptr = '\0';
       multiname = utils::strdup(fmt::format("{}{}{}", filename, icluster, ptr+1));
diff --git a/src/dump.h b/src/dump.h
index bce32c9d65..34e0677af8 100644
--- a/src/dump.h
+++ b/src/dump.h
@@ -16,6 +16,8 @@
 
 #include "pointers.h"    // IWYU pragma: export
 
+#include <map>
+
 namespace LAMMPS_NS {
 
 class Dump : protected Pointers {
@@ -100,6 +102,8 @@ class Dump : protected Pointers {
   char *format_bigint_user;
   char **format_column_user;
   enum { INT, DOUBLE, STRING, BIGINT };
+  std::map<std::string, int> key2col;
+  std::vector<std::string> keyword_user;
 
   FILE *fp;        // file to write dump to
   int size_one;    // # of quantities for one atom
diff --git a/src/dump_atom.cpp b/src/dump_atom.cpp
index 0dbd3b3278..faad91f3c5 100644
--- a/src/dump_atom.cpp
+++ b/src/dump_atom.cpp
@@ -38,6 +38,9 @@ DumpAtom::DumpAtom(LAMMPS *lmp, int narg, char **arg) : Dump(lmp, narg, arg)
   buffer_allow = 1;
   buffer_flag = 1;
   format_default = nullptr;
+  key2col = { { "id", 0 }, { "type", 1 }, { "x", 2 }, { "y", 3 },
+              { "z", 4 }, { "ix", 5 }, { "iy", 6 }, { "iz", 7 } };
+  keyword_user = { "", "", "", "", "", "", "", "" };
 }
 
 /* ---------------------------------------------------------------------- */
@@ -63,15 +66,25 @@ void DumpAtom::init_style()
   domain->boundary_string(boundstr);
 
   // setup column string
+  std::string default_columns;
 
   if (scale_flag == 0 && image_flag == 0)
-    columns = (char *) "id type x y z";
+    default_columns = "id type x y z";
   else if (scale_flag == 0 && image_flag == 1)
-    columns = (char *) "id type x y z ix iy iz";
+    default_columns = "id type x y z ix iy iz";
   else if (scale_flag == 1 && image_flag == 0)
-    columns = (char *) "id type xs ys zs";
+    default_columns = "id type xs ys zs";
   else if (scale_flag == 1 && image_flag == 1)
-    columns = (char *) "id type xs ys zs ix iy iz";
+    default_columns = "id type xs ys zs ix iy iz";
+
+  int icol = 0;
+  columns.clear();
+  for (auto item : utils::split_words(default_columns)) {
+    if (columns.size()) columns += " ";
+    if (keyword_user[icol].size()) columns += keyword_user[icol];
+    else columns += item;
+    ++icol;
+  }
 
   // setup function ptrs
 
@@ -201,9 +214,9 @@ void DumpAtom::header_unit_style_binary()
 
 void DumpAtom::header_columns_binary()
 {
-  int len = strlen(columns);
+  int len = columns.size();
   fwrite(&len, sizeof(int), 1, fp);
-  fwrite(columns, sizeof(char), len, fp);
+  fwrite(columns.c_str(), sizeof(char), len, fp);
 }
 
 /* ---------------------------------------------------------------------- */
@@ -301,7 +314,7 @@ void DumpAtom::header_item(bigint ndump)
   fprintf(fp,"%-1.16e %-1.16e\n",boxxlo,boxxhi);
   fprintf(fp,"%-1.16e %-1.16e\n",boxylo,boxyhi);
   fprintf(fp,"%-1.16e %-1.16e\n",boxzlo,boxzhi);
-  fprintf(fp,"ITEM: ATOMS %s\n",columns);
+  fprintf(fp,"ITEM: ATOMS %s\n",columns.c_str());
 }
 
 /* ---------------------------------------------------------------------- */
@@ -322,7 +335,7 @@ void DumpAtom::header_item_triclinic(bigint ndump)
   fprintf(fp,"%-1.16e %-1.16e %-1.16e\n",boxxlo,boxxhi,boxxy);
   fprintf(fp,"%-1.16e %-1.16e %-1.16e\n",boxylo,boxyhi,boxxz);
   fprintf(fp,"%-1.16e %-1.16e %-1.16e\n",boxzlo,boxzhi,boxyz);
-  fprintf(fp,"ITEM: ATOMS %s\n",columns);
+  fprintf(fp,"ITEM: ATOMS %s\n",columns.c_str());
 }
 
 /* ---------------------------------------------------------------------- */
diff --git a/src/dump_atom.h b/src/dump_atom.h
index 1e1a9315d7..3c67e3de54 100644
--- a/src/dump_atom.h
+++ b/src/dump_atom.h
@@ -36,7 +36,7 @@ class DumpAtom : public Dump {
   int scale_flag;    // 1 if atom coords are scaled, 0 if no
   int image_flag;    // 1 if append box count to atom coords, 0 if no
 
-  char *columns;    // column labels
+  std::string columns;    // column labels
 
   void init_style() override;
   int modify_param(int, char **) override;
diff --git a/src/dump_cfg.cpp b/src/dump_cfg.cpp
index d52dac745f..552607b0a5 100644
--- a/src/dump_cfg.cpp
+++ b/src/dump_cfg.cpp
@@ -53,26 +53,26 @@ DumpCFG::DumpCFG(LAMMPS *lmp, int narg, char **arg) :
 
   if (strcmp(earg[2],"xs") == 0) {
     if (strcmp(earg[3],"ysu") == 0 || strcmp(earg[4],"zsu") == 0)
-      error->all(FLERR,
-                 "Dump cfg arguments can not mix xs|ys|zs with xsu|ysu|zsu");
+      error->all(FLERR,"Dump cfg arguments can not mix xs|ys|zs with xsu|ysu|zsu");
     unwrapflag = 0;
   } else {
     if (strcmp(earg[3],"ys") == 0 || strcmp(earg[4],"zs") == 0)
-      error->all(FLERR,
-                 "Dump cfg arguments can not mix xs|ys|zs with xsu|ysu|zsu");
+      error->all(FLERR,"Dump cfg arguments can not mix xs|ys|zs with xsu|ysu|zsu");
     unwrapflag = 1;
   }
 
   // setup auxiliary property name strings
   // convert 'X_ID[m]' (X=c,f,v) to 'X_ID_m'
 
-  if (nfield > 5) auxname = new char*[nfield];
+  if (nfield > 5) auxname = new char*[nfield-5];
   else auxname = nullptr;
 
   int i = 0;
+  key2col.clear();
+  keyword_user.resize(nfield-5);
   for (int iarg = 5; iarg < nfield; iarg++, i++) {
-    ArgInfo argi(earg[iarg],ArgInfo::COMPUTE|ArgInfo::FIX|ArgInfo::VARIABLE
-                 |ArgInfo::DNAME|ArgInfo::INAME);
+    ArgInfo argi(earg[iarg],ArgInfo::COMPUTE|ArgInfo::FIX|ArgInfo::VARIABLE|
+                 ArgInfo::DNAME|ArgInfo::INAME);
 
     if (argi.get_dim() == 1) {
       std::string newarg = fmt::format("{}_{}_{}", earg[iarg][0], argi.get_name(), argi.get_index1());
@@ -80,6 +80,8 @@ DumpCFG::DumpCFG(LAMMPS *lmp, int narg, char **arg) :
     } else {
       auxname[i] = utils::strdup(earg[iarg]);
     }
+    key2col[earg[iarg]] = i;
+    keyword_user[i].clear();
   }
 }
 
@@ -88,8 +90,8 @@ DumpCFG::DumpCFG(LAMMPS *lmp, int narg, char **arg) :
 DumpCFG::~DumpCFG()
 {
   if (auxname) {
-    for (int i = 0; i < nfield-5; i++) delete [] auxname[i];
-    delete [] auxname;
+    for (int i = 0; i < nfield-5; i++) delete[] auxname[i];
+    delete[] auxname;
   }
 }
 
@@ -136,8 +138,12 @@ void DumpCFG::write_header(bigint n)
   fprintf(fp,"H0(3,3) = %g A\n",domain->zprd);
   fprintf(fp,".NO_VELOCITY.\n");
   fprintf(fp,"entry_count = %d\n",nfield-2);
-  for (int i = 0; i < nfield-5; i++)
-    fprintf(fp,"auxiliary[%d] = %s\n",i,auxname[i]);
+  for (int i = 0; i < nfield-5; i++) {
+    if (keyword_user[i].size())
+      fprintf(fp,"auxiliary[%d] = %s\n",i,keyword_user[i].c_str());
+    else
+      fprintf(fp,"auxiliary[%d] = %s\n",i,auxname[i]);
+  }
 }
 
 /* ----------------------------------------------------------------------
diff --git a/src/dump_custom.cpp b/src/dump_custom.cpp
index 5d371d3145..b22e9d6eec 100644
--- a/src/dump_custom.cpp
+++ b/src/dump_custom.cpp
@@ -55,14 +55,11 @@ enum{LT,LE,GT,GE,EQ,NEQ,XOR};
 DumpCustom::DumpCustom(LAMMPS *lmp, int narg, char **arg) :
   Dump(lmp, narg, arg),
   idregion(nullptr), thresh_array(nullptr), thresh_op(nullptr), thresh_value(nullptr),
-  thresh_last(nullptr), thresh_fix(nullptr),
-  thresh_fixID(nullptr), thresh_first(nullptr),
-  earg(nullptr), vtype(nullptr), vformat(nullptr), columns(nullptr), choose(nullptr),
-  dchoose(nullptr), clist(nullptr), field2index(nullptr),
-  argindex(nullptr), id_compute(nullptr),
-  compute(nullptr), id_fix(nullptr), fix(nullptr),
-  id_variable(nullptr), variable(nullptr),
-  vbuf(nullptr), id_custom(nullptr), custom(nullptr), custom_flag(nullptr),
+  thresh_last(nullptr), thresh_fix(nullptr), thresh_fixID(nullptr), thresh_first(nullptr),
+  earg(nullptr), vtype(nullptr), vformat(nullptr), columns(nullptr), columns_default(nullptr),
+  choose(nullptr), dchoose(nullptr), clist(nullptr), field2index(nullptr), argindex(nullptr),
+  id_compute(nullptr), compute(nullptr), id_fix(nullptr), fix(nullptr), id_variable(nullptr),
+  variable(nullptr), vbuf(nullptr), id_custom(nullptr), custom(nullptr), custom_flag(nullptr),
   typenames(nullptr), pack_choice(nullptr)
 {
   if (narg == 5) error->all(FLERR,"No dump custom arguments specified");
@@ -180,13 +177,14 @@ DumpCustom::DumpCustom(LAMMPS *lmp, int narg, char **arg) :
   // setup column string
 
   cols.clear();
+  keyword_user.resize(nfield);
   for (int iarg = 0; iarg < nfield; iarg++) {
+    key2col[earg[iarg]] = iarg;
+    keyword_user[iarg].clear();
+    if (cols.size()) cols += " ";
     cols += earg[iarg];
-    cols += " ";
   }
-  // remove trailing blank and copy
-  cols.resize(cols.size()-1);
-  columns = utils::strdup(cols);
+  columns_default = utils::strdup(cols);
 }
 
 /* ---------------------------------------------------------------------- */
@@ -257,6 +255,7 @@ DumpCustom::~DumpCustom()
     delete[] format_column_user;
   }
 
+  delete[] columns_default;
   delete[] columns;
 }
 
@@ -264,6 +263,19 @@ DumpCustom::~DumpCustom()
 
 void DumpCustom::init_style()
 {
+  // assemble ITEMS: column string from defaults and user values
+
+  delete[] columns;
+  std::string combined;
+  int icol = 0;
+  for (auto item : utils::split_words(columns_default)) {
+    if (combined.size()) combined += " ";
+    if (keyword_user[icol].size()) combined += keyword_user[icol];
+    else combined += item;
+    ++icol;
+  }
+  columns = utils::strdup(combined);
+  
   // format = copy of default or user-specified line format
 
   delete[] format;
diff --git a/src/dump_custom.h b/src/dump_custom.h
index 5a99cca009..0dcfd82bba 100644
--- a/src/dump_custom.h
+++ b/src/dump_custom.h
@@ -60,6 +60,7 @@ class DumpCustom : public Dump {
   char **vformat;     // format string for each vector element
                       //
   char *columns;      // column labels
+  char *columns_default;
                       //
   int nchoose;        // # of selected atoms
   int maxlocal;       // size of atom selection and variable arrays
diff --git a/src/thermo.cpp b/src/thermo.cpp
index fe6f92d85d..a7d76017f8 100644
--- a/src/thermo.cpp
+++ b/src/thermo.cpp
@@ -631,8 +631,7 @@ void Thermo::modify_params(int narg, char **arg)
     } else if (strcmp(arg[iarg], "colname") == 0) {
       if (iarg + 2 > narg) error->all(FLERR, "Illegal thermo_modify command");
       if (strcmp(arg[iarg + 1], "default") == 0) {
-        for (int i=0; i < nfield_initial + 1; ++i)
-          keyword_user[i].clear();
+        for (auto item : keyword_user) item.clear();
         iarg += 2;
       } else {
         if (iarg + 3 > narg) error->all(FLERR, "Illegal thermo_modify command");
@@ -660,7 +659,7 @@ void Thermo::modify_params(int narg, char **arg)
         format_int_user.clear();
         format_bigint_user.clear();
         format_float_user.clear();
-        for (int i = 0; i < nfield_initial + 1; ++i) format_column_user[i].clear();
+        for (auto item : format_column_user) item.clear();
         iarg += 2;
         continue;
       }