Definition of keep:

part of speech: noun

Condition, as in good keep; a stronghold in the middle of a castle.

part of speech: verb

To hold; to retain, as a thing in one's power or possession; to hold in charge; to protect; to support; to feed; to have the care of; to solemnise, as a day; to detain; to observe; to conceal; to remain in any state; to be durable; to adhere strictly to.