The apple is a fruit; originally, the term simply meant “fruit” in general (as in the terms “crabapple”, “rose apple”, “pineapple”, &c), but is now understood to refer to the sweet, white-fleshed fruit of the tree of the Malus genus. Medieval tradition equated the apple with the Forbidden Fruit in the Garden of Eden, possibly due to the pun (Latin mālum, apple, and malum, evil).
Apples are found in period armory, as in the canting arms of Holtzapfel, 1605 [Siebmacher 196]. They should be depicted in the period round form; apples drawn as a more modern cultivar, such as the trapezoidal “Red Delicious”, are a step from period practice. The Society default is with slip to chief, which seems to be the opposite of medieval convention. The illustration shows an apple slipped and leaved.
Adelicia Tagliaferro bears: Sable, an apple argent.
Cai ap Cai bears: Per pale argent and gules, in pale two apples counterchanged.
Da’ud ibn Auda bears as a badge: An apple gules slipped and leaved proper.