spinster

Etymology

From Middle English spinnestere (“female spinner of thread”) (late 14th century),^[1][2] formed from English spin + -ster.^[2][3][4]

Because unmarried women were expected to occupy themselves with spinning, from the 1600s the word became the legal designation in England of unmarried women,^[2][5] and by 1719 was used generically of a woman still unmarried beyond the usual age.^[2] Compare Middle Dutch and Dutch spinster.^[3]

References

1. [1] The American Heritage Dictionary of the English Language, Boston: Houghton Mifflin
2. [1] [2] [3] [4] Harper, Douglas, Online Etymology Dictionary, https://www.etymonline.com
3. [1] [2] Simpson, J. A.; Weiner, E. S. C., eds. (1989), The Oxford English Dictionary, 2nd ed., Oxford: Clarendon Press
4. [1] Random House Webster's Unabridged Dictionary, New York: Random House
5. [1] Wiktionary, the free dictionary, https://en.wiktionary.org