(baseball) the slight elevation on which the pitcher stands
"The batter stepped up to home plate, waiting anxiously for the pitcher to wind up and release a fastball from the mound."
a collection of objects laid on top of each other
"The children built a tall mound of discarded leaves in the backyard."
An artificial hill or elevation of earth; a raised bank; an embankment thrown up for defense
"The soldiers quickly built a mound of dirt around the fort to protect themselves from enemy arrows."
In plain English: A mound is a small hill of dirt, sand, or other material that rises up from the ground.
"The gardeners built a mound with soil to help their flowers grow better."
Usage: Use "mound" as a verb only when describing the act of piling something up or constructing a defensive earthwork, not simply placing an object on top of another surface. Avoid confusing this term with "heap," which implies a less structured accumulation without specific defensive intent.
To fortify with a mound; add a barrier, rampart, etc. to.
"The soldiers quickly mounded sandbags around the gate to create a defensive barrier against the approaching enemy."
In plain English: To mound something means to pile it up into a heap.
"The children mounded sand in their backyard to build a castle."
The word mound originally meant "hedge" or a protective boundary in Middle English. It traveled into modern usage to describe an earthen rampart, evolving from its ancient roots meaning simply "hand."