English word K-9 unit comes from Latin canem, Latin -inus, and later Latin caninus (Canine; of or pertaining to a dog.)

Detailed word origin of K-9 unit

Dictionary entry	Language	Definition
canem	Latin (lat)
-inus	Latin (lat)	Of or pertaining to; -ine; usually indicates a relationship of position, possession, or origin.
caninus	Latin (lat)	Canine; of or pertaining to a dog.
canine	English (eng)	(anatomy) Of or pertaining to mammalian teeth which are cuspids or fangs.. Dog-like.. Of, or pertaining to, a dog or dogs. (formal) Any of certain extant canids regarded as similar to the dog or wolf (including coyotes, jackals, etc.) but distinguished from the vulpines, which are regarded as fox-like.. (poker slang) A king and a nine as a starting hand in Texas hold 'em due to phonetic [...]
K-9 unit	English (eng)	(US) A police dog or a police dog and its handler.

Words with the same origin as K-9 unit