Etymology

Noun

1. The meat from a cow, bull or other bovine.

   I hate eating beef.

2. Would be "a side of beef". A chunk, cut or piece not being the whole piece, cf ham.
3. A generic term for a cow or bull.

   Do you want to raise beeves?

4. a complaint or disagreement

   He has a beef with anyone who tells him otherwise.

Verb

1. To complain.
2. To add weight or strength to, usually as beef up.

   Since you stopped running, you are really beefing out.