Gee and Gee-gee

Gee noun - A unit of force equal to the force exerted by gravity; used to indicate the force to which a body is subjected when it is accelerated.

Gee-gee and gee are semantically related. In some cases you can use "Gee-gee" instead a noun "Gee".

Gee-gee noun - A word for horse used by children or in adult slang.

Gee and gee-gee are semantically related. You can use "Gee" instead a noun phrase "Gee-gee".