apple

The fruit of the tree Malus domestica, chiefly with a green, red, or yellow skin, cultivated in temperate climates for cidermaking, cooking, and eating.

Often with a qualifying word: any fruit or vegetable, or any other thing (such as a cone or gall) produced by a plant, especially if from a tree and similar to the fruit of Malus domestica (noun sense 1.1).

Something which resembles the fruit of Malus domestica (noun sense 1.1) in shape (such as a ball, breast, or globe) or colour.

Ellipsis of Adam's apple (“the lump in the throat, usually more noticeable in men than in women; the laryngeal prominence”).

Ellipsis of apple-green (“a bright green colour with a light tint of yellow, like that of a Granny Smith apple”).

Ellipsis of apple of the eye (“the pupil, or pupil and iris, of the eye, originally believed to be spherical; also, the eyeball”).

The round, fleshy part of a cheek between the eye and the corner of the mouth when a person is smiling.

The surface of revolution of a circular arc of an angle greater than 180° rotated about the straight line passing through the arc's two endpoints.

In full apple bowl: a round bowl of a tobacco pipe; also, a tobacco pipe with such a bowl.

In full old apple: a baseball.