diff --git a/config.h.cmake.in b/config.h.cmake.in
index 611ceb7a0..2710361df 100644
--- a/config.h.cmake.in
+++ b/config.h.cmake.in
@@ -109,7 +109,6 @@ are set when opening a binary file on Windows. */
 
 /* if true, enable CDF5 Support */
 #cmakedefine ENABLE_CDF5 1
-#cmakedefine USE_CDF5 1
 
 /* if true, enable strict null byte header padding. */
 #cmakedefine USE_STRICT_NULL_BYTE_HEADER_PADDING 1
diff --git a/configure.ac b/configure.ac
index 5864395c4..2bf1b5ac3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -906,11 +906,8 @@ fi
 AC_MSG_RESULT($enable_cdf5)
 
 if test "x${enable_cdf5}" = xyes; then
-   AC_DEFINE([USE_CDF5], [1], [if true, enable CDF5 Support])
    AC_DEFINE([ENABLE_CDF5], [1], [if true, enable CDF5 Support])
 fi
-
-AM_CONDITIONAL(USE_CDF5, [test x$enable_cdf5 = xyes ])
 AM_CONDITIONAL(ENABLE_CDF5, [test x$enable_cdf5 = xyes ])
 
 $SLEEPCMD
diff --git a/libdispatch/dfile.c b/libdispatch/dfile.c
index 99c926e5c..98d1681bc 100644
--- a/libdispatch/dfile.c
+++ b/libdispatch/dfile.c
@@ -2106,7 +2106,7 @@ NC_create(const char *path0, int cmode, size_t initialsz,
 	    model = NC_FORMATX_NC4;
 	    break;
 #endif
-#ifdef USE_CDF5
+#ifdef ENABLE_CDF5
 	 case NC_FORMAT_CDF5:
 	    xcmode |= NC_64BIT_DATA;
 	    model = NC_FORMATX_NC3;
@@ -2322,7 +2322,7 @@ NC_open(const char *path0, int cmode, int basepe, size_t *chunksizehintp,
         hdf4built = 1;
   #endif
 #endif
-#ifdef USE_CDF5
+#ifdef ENABLE_CDF5
        cdf5built = 1;
 #endif
        if(!hdf5built && model == NC_FORMATX_NC4) {
diff --git a/libsrc/nc3internal.c b/libsrc/nc3internal.c
index fb99798d9..102e2a3ca 100644
--- a/libsrc/nc3internal.c
+++ b/libsrc/nc3internal.c
@@ -100,7 +100,7 @@ err:
 int
 nc3_cktype(int mode, nc_type type)
 {
-#ifdef USE_CDF5
+#ifdef ENABLE_CDF5
     if (mode & NC_CDF5) { /* CDF-5 format */
         if (type >= NC_BYTE && type < NC_STRING) return NC_NOERR;
     } else
@@ -1167,7 +1167,7 @@ nc_set_default_format(int format, int *old_formatp)
       return NC_EINVAL;
 #else
     if (format != NC_FORMAT_CLASSIC && format != NC_FORMAT_64BIT_OFFSET
-#ifdef USE_CDF5
+#ifdef ENABLE_CDF5
         && format != NC_FORMAT_CDF5
 #endif
         )
@@ -1698,7 +1698,7 @@ NC3_inq_format(int ncid, int *formatp)
       return NC_NOERR;
 
    /* only need to check for netCDF-3 variants, since this is never called for netCDF-4 files */
-#ifdef USE_CDF5
+#ifdef ENABLE_CDF5
    if (fIsSet(nc3->flags, NC_64BIT_DATA))
       *formatp = NC_FORMAT_CDF5;
    else
diff --git a/nc_test/Makefile.am b/nc_test/Makefile.am
index e92a04dc0..841995c30 100644
--- a/nc_test/Makefile.am
+++ b/nc_test/Makefile.am
@@ -27,7 +27,7 @@ endif
 
 if TEST_PARALLEL4
 if USE_PNETCDF
-if USE_CDF5
+if ENABLE_CDF5
 TESTPROGRAMS += tst_cdf5format
 endif
 endif
diff --git a/nc_test/nc_test.c b/nc_test/nc_test.c
index 5800c339e..9e5490e82 100644
--- a/nc_test/nc_test.c
+++ b/nc_test/nc_test.c
@@ -134,7 +134,7 @@ main(int argc, char *argv[])
 	     break;
 
 	  case NC_FORMAT_CDF5:
-#ifdef USE_CDF5
+#ifdef ENABLE_CDF5
         nc_set_default_format(NC_FORMAT_CDF5, NULL);
 	     fprintf(stderr, "\n\nSwitching to 64-bit data format.\n");
 	     strcpy(testfile, "nc_test_cdf5.nc");
diff --git a/nc_test/t_nc.c b/nc_test/t_nc.c
index ec3be5e0e..afddd61d5 100644
--- a/nc_test/t_nc.c
+++ b/nc_test/t_nc.c
@@ -361,7 +361,7 @@ main(int argc, char *argv[])
 	MPI_Init(&argc, &argv);
 
     cmode |= (NC_PNETCDF);
-#ifdef USE_CDF5
+#ifdef ENABLE_CDF5
 	cmode |= (NC_64BIT_DATA);
 #endif
 	ret = nc_create_par(fname,cmode, MPI_COMM_WORLD, MPI_INFO_NULL, &id);
diff --git a/nc_test/test_write.m4 b/nc_test/test_write.m4
index edc303aed..4650e3706 100644
--- a/nc_test/test_write.m4
+++ b/nc_test/test_write.m4
@@ -2424,7 +2424,7 @@ APIFunc(get_file_version)(char *path, int *version)
    if (strncmp(magic, "CDF", MAGIC_NUM_LEN-1)==0) {
       if (magic[MAGIC_NUM_LEN-1] == NC_FORMAT_CLASSIC ||
           magic[MAGIC_NUM_LEN-1] == NC_FORMAT_64BIT_OFFSET
-#ifdef USE_CDF5
+#ifdef ENABLE_CDF5
           || magic[MAGIC_NUM_LEN-1] == NC_FORMAT_CDF5
 #endif
 )
diff --git a/nc_test/tst_def_var_fill.c b/nc_test/tst_def_var_fill.c
index 96e7f9145..affd3156e 100644
--- a/nc_test/tst_def_var_fill.c
+++ b/nc_test/tst_def_var_fill.c
@@ -54,7 +54,7 @@ int main(int argc, char** argv) {
     buf = (int*) malloc(NY*NX * sizeof(int));
 
     for (k=0; k<5; k++) {
-#ifndef USE_CDF5
+#ifndef ENABLE_CDF5
         if (formats[k] == NC_FORMAT_CDF5) continue;
 #endif
 #ifndef USE_NETCDF4
diff --git a/nc_test/tst_global_fillval.c b/nc_test/tst_global_fillval.c
index 5058eb7e4..4812d3f72 100644
--- a/nc_test/tst_global_fillval.c
+++ b/nc_test/tst_global_fillval.c
@@ -37,7 +37,7 @@ main(int argc, char **argv)
     num_formats += 2;
 #endif
 
-#ifdef USE_CDF5
+#ifdef ENABLE_CDF5
     num_formats++;
 #endif
 
@@ -46,7 +46,7 @@ main(int argc, char **argv)
 
 	formats[n++] = 0;
 	formats[n++] = NC_64BIT_OFFSET;
-#ifdef USE_CDF5
+#ifdef ENABLE_CDF5
 	formats[n++] = NC_64BIT_DATA;
 #endif
 #ifdef USE_NETCDF4
diff --git a/nc_test/tst_names.c b/nc_test/tst_names.c
index 8127f1b56..5f63c43e4 100644
--- a/nc_test/tst_names.c
+++ b/nc_test/tst_names.c
@@ -225,7 +225,7 @@ main(int argc, char **argv)
        NC_FORMAT_CLASSIC
        ,
        NC_FORMAT_64BIT_OFFSET
-#ifdef USE_CDF5
+#ifdef ENABLE_CDF5
        ,
        NC_FORMAT_CDF5
 #endif
diff --git a/nc_test/tst_small.c b/nc_test/tst_small.c
index 114218f44..60ef9a5c0 100644
--- a/nc_test/tst_small.c
+++ b/nc_test/tst_small.c
@@ -55,7 +55,7 @@ static int file_create(const char *filename, int cmode, int *ncid)
 #ifdef USE_PNETCDF
     if (default_format == NC_FORMAT_CLASSIC ||
         default_format == NC_FORMAT_64BIT_OFFSET
-#ifdef USE_CDF5
+#ifdef ENABLE_CDF5
         || default_format == NC_FORMAT_64BIT_DATA
 #endif
         )
@@ -525,7 +525,7 @@ main(int argc, char **argv)
 	    printf("Switching to 64-bit offset format.\n");
 	    strcpy(testfile, "tst_small_64bit.nc");
 	    break;
-#ifdef USE_CDF5
+#ifdef ENABLE_CDF5
 	 case NC_FORMAT_CDF5:
 	    nc_set_default_format(NC_FORMAT_CDF5, NULL);
 	    printf("Switching to 64-bit data format.\n");
diff --git a/ncdump/nccopy.c b/ncdump/nccopy.c
index f5f033a3a..5a8901ec8 100644
--- a/ncdump/nccopy.c
+++ b/ncdump/nccopy.c
@@ -1706,7 +1706,7 @@ copy(char* infile, char* outfile)
 	create_mode |= NC_64BIT_OFFSET;
 	break;
     case NC_FORMAT_CDF5:
-#ifdef USE_CDF5
+#ifdef ENABLE_CDF5
       create_mode |= NC_64BIT_DATA;
       break;
 #else
diff --git a/ncdump/run_ncgen_tests.sh b/ncdump/run_ncgen_tests.sh
index eb516e12d..752072ae3 100755
--- a/ncdump/run_ncgen_tests.sh
+++ b/ncdump/run_ncgen_tests.sh
@@ -11,7 +11,7 @@ set -e
 # This shell script runs the ncdump tests.
 # get some config.h parameters
 if test -f ${top_builddir}/config.h ; then
-  if fgrep -e '#define USE_CDF5 1' ${top_builddir}/config.h >/dev/null ; then
+  if fgrep -e '#define ENABLE_CDF5 1' ${top_builddir}/config.h >/dev/null ; then
     CDF5=1
   else
     CDF5=0
@@ -51,7 +51,7 @@ echo "*** creating 64-bit offset file c0_64_run_ncgen_tests.nc from c0.cdl..."
 
 validateNC c0 "c0_64" -k 64-bit-offset -b
 
-if test "x$USE_CDF5" = x1 ; then
+if test "x$ENABLE_CDF5" = x1 ; then
 
     echo "*** creating 64-bit data file c5.nc from c5.cdl..."
     ${NCGEN} -k 64-bit-data -b -o tst_c5_run_ncgen_tests.nc $top_srcdir/ncgen/c5.cdl
diff --git a/ncdump/tst_64bit.sh b/ncdump/tst_64bit.sh
index 838dabfcd..861b01998 100755
--- a/ncdump/tst_64bit.sh
+++ b/ncdump/tst_64bit.sh
@@ -8,7 +8,7 @@ if test "x$srcdir" = x ; then srcdir=`pwd`; fi
 # This shell script runs the ncdump tests.
 # get some config.h parameters
 if test -f ${top_builddir}/config.h ; then
-  if fgrep -e '#define USE_CDF5 1' ${top_builddir}/config.h >/dev/null ; then
+  if fgrep -e '#define ENABLE_CDF5 1' ${top_builddir}/config.h >/dev/null ; then
     CDF5=1
   else
     CDF5=0
diff --git a/ncdump/tst_dimsizes.c b/ncdump/tst_dimsizes.c
index edb0eb80d..376a199d8 100644
--- a/ncdump/tst_dimsizes.c
+++ b/ncdump/tst_dimsizes.c
@@ -12,7 +12,7 @@
 #define DIMMAXCLASSIC (NC_MAX_INT - 3)
 #define DIMMAX64OFFSET (NC_MAX_UINT - 3)
 
-#ifdef USE_CDF5
+#ifdef ENABLE_CDF5
 #define DIMMAX64DATA (NC_MAX_UINT64 - 3)
 #endif
 
@@ -66,7 +66,7 @@ main(int argc, char **argv)
     if(dimsize != DIMMAX64OFFSET) ERR;
     if ((stat=nc_close(ncid))) ERRSTAT(stat);
 
-#ifdef USE_CDF5
+#ifdef ENABLE_CDF5
     if(sizeof(size_t) == 8) {
       printf("\n*** Writing Max Dimension Size (%llu) For NC_64BIT_DATA\n",DIMMAX64DATA);
         if ((stat=nc_create(FILE64DATA, NC_CLOBBER | NC_64BIT_DATA, &ncid))) ERRSTAT(stat);
@@ -81,7 +81,7 @@ main(int argc, char **argv)
 	if(dimsize != DIMMAX64DATA) ERR;
 	if ((stat=nc_close(ncid))) ERRSTAT(stat);
     }
-#endif /* USE_CDF5 */
+#endif /* ENABLE_CDF5 */
 
     SUMMARIZE_ERR;
     FINAL_RESULTS;
diff --git a/ncdump/tst_formatx3.sh b/ncdump/tst_formatx3.sh
index 548b56bf9..ea395e400 100755
--- a/ncdump/tst_formatx3.sh
+++ b/ncdump/tst_formatx3.sh
@@ -6,10 +6,10 @@ if test "x$srcdir" = x ; then srcdir=`pwd`; fi
 # This shell script runs the ncdump tests.
 # get some config.h parameters
 if test -f ${top_builddir}/config.h ; then
-  if fgrep -e '#define USE_CDF5 1' ${top_builddir}/config.h >/dev/null ; then
-    USE_CDF5=1
+  if fgrep -e '#define ENABLE_CDF5 1' ${top_builddir}/config.h >/dev/null ; then
+    ENABLE_CDF5=1
   else
-    USE_CDF5=0
+    ENABLE_CDF5=0
   fi
 else
   echo "Cannot locate config.h"
@@ -42,9 +42,9 @@ ECODE=1
 fi
 
 
-# Only do following test if USE_CDF5 is true.
+# Only do following test if ENABLE_CDF5 is true.
 
-if test "x$USE_CDF5" = x1 ; then
+if test "x$ENABLE_CDF5" = x1 ; then
     echo "Test extended format output for a 64-bit CDF-5 classic file"
     rm -f tmp_tst_formatx3
     ${NCGEN} -k5 -b -o ./tst_formatx3.nc $srcdir/ref_tst_small.cdl
diff --git a/ncdump/tst_lengths.sh b/ncdump/tst_lengths.sh
index dbe5c6810..a21f6a404 100755
--- a/ncdump/tst_lengths.sh
+++ b/ncdump/tst_lengths.sh
@@ -5,7 +5,7 @@ if test "x$srcdir" = x ; then srcdir=`pwd`; fi
 
 # get some config.h parameters
 if test -f ${top_builddir}/config.h ; then
-  if fgrep -e '#define USE_CDF5 1' ${top_builddir}/config.h >/dev/null ; then
+  if fgrep -e '#define ENABLE_CDF5 1' ${top_builddir}/config.h >/dev/null ; then
     HAVE_CDF5=1
   else
     HAVE_CDF5=0
diff --git a/ncdump/tst_nccopy3.sh b/ncdump/tst_nccopy3.sh
index 1b023e549..449e89686 100755
--- a/ncdump/tst_nccopy3.sh
+++ b/ncdump/tst_nccopy3.sh
@@ -13,7 +13,7 @@ echo ""
 
 # get some config.h parameters
 if test -f ${top_builddir}/config.h ; then
-  if fgrep -e '#define USE_CDF5 1' ${top_builddir}/config.h >/dev/null ; then
+  if fgrep -e '#define ENABLE_CDF5 1' ${top_builddir}/config.h >/dev/null ; then
     HAVE_CDF5=1
   else
     HAVE_CDF5=0
diff --git a/ncgen/main.c b/ncgen/main.c
index 45c1336bd..8af6909cd 100644
--- a/ncgen/main.c
+++ b/ncgen/main.c
@@ -512,7 +512,7 @@ main(
 
     /* Compute the k_flag (1st pass) using rules in the man page (ncgen.1).*/
 
-#ifndef USE_CDF5
+#ifndef ENABLE_CDF5
     if(k_flag == NC_FORMAT_CDF5) {
       derror("Output format CDF5 requested, but netcdf was built without cdf5 support.");
       return 0;