a man who has never been married
"After ten years of dating, John finally decided to stop calling himself a bachelor and start looking for a wife."
a knight of the lowest order; could display only a pennon
"The young bachelor knelt before the duke to present his small red pennon, knowing he was too low in rank to fly a full banner."
A person, especially a man, who is socially regarded as able to marry, but has not yet.
"Despite his many suitors and ready reputation for marriage, John remained a bachelor because he had never found the right partner."
In plain English: A bachelor is an unmarried man who lives alone and has no wife.
"The single bachelor lived alone in his small apartment downtown."
Usage: Use "bachelor" to refer specifically to an unmarried man, distinguishing him from women or married individuals. Avoid using it as a general term for any single person regardless of marital status.
The word bachelor comes from the medieval Latin term baccalarius, which originally referred to a squire or young knight. It entered English through Anglo-Norman and Old French before evolving to describe an unmarried man.