From BiblePortal Wikipedia

Webster's Dictionary [1]

(1): ( n.) An olive tree.

(2): ( n.) A small tilt hammer, worked by the foot.

(3): ( n.) An olive grove.

The Nuttall Encyclopedia [2]

A favourite paladin of Charlemagne's, who, along with Roland, rode by his side, and whose name, along with Roland's, has passed into the phrase, a "Roland for an Oliver," meaning one good masterstroke for another, such as both these knights never failed to deliver.