from Wiktionary, Creative Commons Attribution/Share-Alike License
- proper n. A London borough where once upon a time many horses were pastured.
- proper n. One of several breeds of compact English horses.
- proper n. An English habitational surname.
- proper n. (A means of transportation that is) available for public hire.
The senses "a horse" and "(a means of transport) available for hire" derive from the fact that many horses were kept in the London borough of Hackney, and were available for hire. The place name is from Old English Hacan ieg "Hacan's Isle" (or "Hook's Island"), referring to dry land in a marsh. (Wiktionary)