Why is the college degree called a "Bachelor's" degree?

The origins of the word “bachelor” are obscure. In English it originally meant a knight who followed another knight’s banner, or a young man who hoped to become a knight. This implies a kind of junior status among knights, and this may be the idea behind its later use for the lowest university degree (below master and doctor). (It was also used at one time for a junior member of a trade guild.)

How it came to mean an unmarried man is not clear. Maybe, in an age when most people married, the unmarried men would tend to be the young and those who hadn’t yet made their mark in a profession.

In the academic sense, it is sometimes said to be derived from “bacca lauri,” (laurel berry) and “baccalaureus” is established as the Latin form in university use, but this derivation is not correct.

(See Oxford English Dictionary and Oxford Dictionary of Word Origins).

I just read it was named after the laurel wreath the new graduate was crowned with, called the baccalaureate, Anglicised as bachelor. We use a mortar board now but the principle remains the same. Chamber's dictionary says it's also ultimately of doubtful origin though, so the sides are split.