What is the word for an unmarried female? [closed]

Solution 1:

Bachelorette is an American English term for an unmarried woman. A bachelorette may have once been in a marriage or pair bonding relationship that produced children in her past. The term is derived from the word bachelor.

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Solution 2:

The word is "spinster", but it has completely different connotations. "Bachelor" often implies "young, free and single" whereas "spinster" often is more "lonely, old, left-on-the-shelf".

Solution 3:

Maiden is also acceptable though somewhat ambiguous and antiquated.
According to part of the Online Etymology Dictionary entry on maiden:

... fem. variant of PIE base *maghu- "youngster of either sex, unmarried person" (cf. O.E. magu "child, son," Avestan magava- "unmarried," O.Ir. maug "slave").