1. Quince: Middle English plural of Old French cooin, from Latin for apple of Cydonia, now Chania, Crete.
2. Stamina: Latin plural of stamen, thread or essential element, before it was applied by analogy to flower parts.
3. Chintz: Plural of chint, a stained or painted calico cloth imported from India, from Hindi chimt, spattering, stain.
4. Pox: Plural of pock, as in pock-marked.
5. Truce: Plural of true, Middle English, in the sense of belief, trust.
6. Invoice: Plural of obsolete invoy, from French envoy, envoyer, to send.
7. Broccoli: Italian, plural of broccolo, cabbage sprout, head, diminutive of brocco, shoot.
8. Dismal: Originally a noun, for the two days in each month which were believed to be unlucky, from Anglo-Norman French dis mal, and medieval Latin dies mali, evil days.
9. Sweden: Originally a plural of Swede, a Swedish person.