What is the meaning of the word "oat"?

Oats are an important food crop and are valued for their mild flavor and numerous health benefits, making them a favored ingredient in many diets worldwide.

Definitions:

A grain that is widely grown for its long loose clusters of seeds which are used for human food and for livestock feed. NOUN
- Oat silage, fermented oats used as animal feed, provides essential nutrients for livestock.
A type of cereal grain known for their seed, used for food, feed, and foder. NOUN
- Oat groats, the whole and unprocessed form of oats, can be cooked in various ways.
Annual grass of Europe and North Africa. NOUN
- Oat straw, used in herbal teas, has calming and sedative properties.
Seed of the annual grass Avena sativa. NOUN
- Oat bran, the outer layer of oats, is high in fiber and can aid digestion.