Step 1: Distinguish the homophone pair.
"Altar" and "Alter" sound identical but mean completely different things; "Alter" (with an e) is a verb meaning to change something; "Altar" (with an a) is a noun referring to a sacred place.
Step 2: Define Altar.
An Altar is a raised table or platform used in religious ceremonies for offerings, sacrifices, worship, or prayer; it is found in churches, temples, and other places of worship.
Step 3: Apply the memory trick and confirm.
Memory tip: "Altar" ends in "ar" - think of it as where you go to pray; the correct meaning is "place of offering."
\[ \boxed{\text{Place of offering}} \]