thornback

noun

1. Any animal with a thorny back, especially marine animals, such as:
2. Any animal with a thorny back, especially marine animals, such as:
3. Any animal with a thorny back, especially marine animals, such as:
4. (archaic)A woman over a certain age (variously 26 or 30) who has never married, older than a spinster.

   “[A] society of honest gentlemen [is holding a lottery] for the benefit of all single ladies, widows, maids, or thornbacks […]”

   “Spinsters. — In a society where marriages were formed very early, girls often wedding at sixteen or under, […] At the age of thirty a spinster was called a "thornback ,” but bachelors and thornbacks were not the only people who […]”

   “"And I'll be a thornback spinster! Oh, I'd rather die of the pox than that!" She bolted away to spill her bitter tears out of doors in a place where no one could observe her. Her bold adventure had suddenly turned against her.”