Definition of middle leg in US English:

middle leg

noun

  • 1Slang. A man's penis.

  • 2Entomology. Either of the middle pair of an insect's legs, between the forelegs and the hind legs.

Origin

Mid 16th century (in an earlier sense). From middle + leg.

Pronunciation

middle leg

/ˌmɪdl ˈlɛɡ/