source: Watch The Bachelor TV Show - ABC.com

1. a man who is not and has never been married:

e.g. one of the country's most eligible bachelors

e.g. Mark is a confirmed bachelor.

a confirmed bachelor: 独身主義者 (!｟報道｠ では同性愛者をさすことも多い)

Zoology a male bird or mammal without a mate, especially one prevented from breeding by a dominant male.

(繁殖地に入れない)若い雄のオットセイ

2. a person who holds an undergraduate degree from a university or college (only in titles or set expressions):

〖通例B-〗学士(→ doctor, master)

e.g. a Bachelor of Arts

e.g. he graduated with a bachelor's degree in philosophy.

3. historical a young knight serving under another's banner. See also knight bachelor.said to be from French bas chevalier, literally ‘low knight’ (i.e. knight of a low order).

〘史〙 (ほかの騎士に従う)若い騎士

bachelorhood | ˈbaCH(ə)lərˌho͝od | noun

Middle English: from Old French bacheler; of uncertain origin.