diff --git a/sys/vm/uma.h b/sys/vm/uma.h
index ef195c65b16f..70f598dfbfee 100644
--- a/sys/vm/uma.h
+++ b/sys/vm/uma.h
@@ -197,24 +197,23 @@ uma_zone_t uma_zcreate(const char *name, size_t size, uma_ctor ctor,
  *		ctor/dtor/zinit/zfini may all be null, see notes above.
  *		Note that the zinit and zfini specified here are NOT
  *		exactly the same as the init/fini specified to uma_zcreate()
- *		when creating a master zone.  These zinit/zfini are called
+ *		when creating a primary zone.  These zinit/zfini are called
  *		on the TRANSITION from keg to zone (and vice-versa). Once
  *		these are set, the primary zone may alter its init/fini
  *		(which are called when the object passes from VM to keg)
  *		using uma_zone_set_init/fini()) as well as its own
- *		zinit/zfini (unset by default for master zone) with
+ *		zinit/zfini (unset by default for primary zone) with
  *		uma_zone_set_zinit/zfini() (note subtle 'z' prefix).
  *
- *	master  A reference to this zone's Master Zone (Primary Zone),
- *		which contains the backing Keg for the Secondary Zone
- *		being added.
+ *	primary A reference to this zone's Primary Zone which contains the
+ *		backing Keg for the Secondary Zone being added.
  *
  * Returns:
  *	A pointer to a structure which is intended to be opaque to users of
  *	the interface.  The value may be null if the wait flag is not set.
  */
 uma_zone_t uma_zsecond_create(const char *name, uma_ctor ctor, uma_dtor dtor,
-    uma_init zinit, uma_fini zfini, uma_zone_t master);
+    uma_init zinit, uma_fini zfini, uma_zone_t primary);
 
 /*
  * Create cache-only zones.
diff --git a/sys/vm/uma_core.c b/sys/vm/uma_core.c
index 6c98d6d9582f..9566ce6d79cd 100644
--- a/sys/vm/uma_core.c
+++ b/sys/vm/uma_core.c
@@ -2197,7 +2197,7 @@ keg_ctor(void *mem, int size, void *udata, int flags)
 	keg->uk_dr.dr_iter = 0;
 
 	/*
-	 * The master zone is passed to us at keg-creation time.
+	 * The primary zone is passed to us at keg-creation time.
 	 */
 	zone = arg->zone;
 	keg->uk_name = zone->uz_name;
@@ -2808,7 +2808,7 @@ uma_startup1(vm_offset_t virtual_avail)
 {
 	struct uma_zctor_args args;
 	size_t ksize, zsize, size;
-	uma_keg_t masterkeg;
+	uma_keg_t primarykeg;
 	uintptr_t m;
 	int domain;
 	uint8_t pflag;
@@ -2838,7 +2838,7 @@ uma_startup1(vm_offset_t virtual_avail)
 	m += zsize;
 	kegs = (uma_zone_t)m;
 	m += zsize;
-	masterkeg = (uma_keg_t)m;
+	primarykeg = (uma_keg_t)m;
 
 	/* "manually" create the initial zone */
 	memset(&args, 0, sizeof(args));
@@ -2848,7 +2848,7 @@ uma_startup1(vm_offset_t virtual_avail)
 	args.dtor = keg_dtor;
 	args.uminit = zero_init;
 	args.fini = NULL;
-	args.keg = masterkeg;
+	args.keg = primarykeg;
 	args.align = UMA_SUPER_ALIGN - 1;
 	args.flags = UMA_ZFLAG_INTERNAL;
 	zone_ctor(kegs, zsize, &args, M_WAITOK);
@@ -3024,13 +3024,13 @@ uma_zcreate(const char *name, size_t size, uma_ctor ctor, uma_dtor dtor,
 /* See uma.h */
 uma_zone_t
 uma_zsecond_create(const char *name, uma_ctor ctor, uma_dtor dtor,
-    uma_init zinit, uma_fini zfini, uma_zone_t master)
+    uma_init zinit, uma_fini zfini, uma_zone_t primary)
 {
 	struct uma_zctor_args args;
 	uma_keg_t keg;
 	uma_zone_t res;
 
-	keg = master->uz_keg;
+	keg = primary->uz_keg;
 	memset(&args, 0, sizeof(args));
 	args.name = name;
 	args.size = keg->uk_size;
diff --git a/sys/vm/uma_int.h b/sys/vm/uma_int.h
index e7b5d9ca51cd..3c154ca75a47 100644
--- a/sys/vm/uma_int.h
+++ b/sys/vm/uma_int.h
@@ -97,8 +97,8 @@
  * safely only from their associated CPU, while the Zones backed by the same
  * Keg all share a common Keg lock (to coalesce contention on the backing
  * slabs).  The backing Keg typically only serves one Zone but in the case of
- * multiple Zones, one of the Zones is considered the Master Zone and all
- * Zone-related stats from the Keg are done in the Master Zone.  For an
+ * multiple Zones, one of the Zones is considered the Primary Zone and all
+ * Zone-related stats from the Keg are done in the Primary Zone.  For an
  * example of a Multi-Zone setup, refer to the Mbuf allocation code.
  */