The difference between Heap up and Mound

Heap up as a verb (intransitive):

To increase over a period of time; to accumulate.

Heap up as a verb (transitive):

To make an untidy pile of (something).

Mound as a noun:

An artificial hill or elevation of earth; a raised bank; an embankment thrown up for defense

Mound as a noun:

A natural elevation appearing as if thrown up artificially; a regular and isolated hill, hillock, or knoll.

Mound as a noun (baseball):

Elevated area of dirt upon which the pitcher stands to pitch.

Mound as a noun:

A ball or globe forming part of the regalia of an emperor or other sovereign. It is encircled with bands, enriched with precious stones, and surmounted with a cross.

Mound as a noun (US, vulgar, slang):

The mons veneris.

Mound as a noun (obsolete, anatomy, measurement, figuratively):

A hand.

Mound as a noun (obsolete):

A protection; restraint; curb.

Mound as a noun (obsolete):

A helmet.

Mound as a noun (obsolete):

Might; size.

Mound as a verb (transitive):

To fortify with a mound; add a barrier, rampart, etc. to.

Mound as a verb (transitive):

To force or pile into a mound or mounds.