having a ridge or shaped like a ridge or the keel of a ship; "a carinate sepal"

Having a conspicuous sharp fold or ridge along the back of a compressed sheath, blade, glume or lemma, especially in Bromus.

of leaves, petals or bracts, folded and ridged along the midrib.

Bearing a longitudinal medial ridge.

Having a longitudinal ridge.

The lower petal or petals when shaped like the keel on a boat.

Resembling the keel of a boat, it's the sharp edge frequently found on the corner of cabriole legs.