oat

Widely cultivated cereal grass, typically Avena sativa.

The oat stalks made good straw.

The main forms of oat are meal and bran.

Any of the numerous species, varieties, or cultivars of any of several similar grain plants in genus Avena.

The wild red oat is thought to be the ancestor of modern food oats.

The seeds of the oat, a grain, harvested as a food crop and for animal feed.

[…]I could munch your good dry Oates. Me-thinkes I haue a great deſire to a bottle of hay: good hay, ſweete hay hath no fellow.

The point is, except in Scotland, people eat comparatively few oats. Scotland's another story, though you'll have to decide how seriously to take it. The way the story goes is that in eastern Scotland, the unmarried plowmen didn't eat anything but oats and milk, except for an occasional potato.

A simple musical pipe made of oat-straw.

The tiniest amount; a whit or jot.

Few of them care an oat for the niceties of the arrow sport, but for the young lords that may be on a hunt!

Alternative letter-case form of OAT.

Initialism of of all time.