Jack

Jakobo

(anglicized form of Jacques)

Joĉjo

(pet name of John)

Ĵakvo

(pet name of John)

azeno

(male ass (the animal))

jako

(military: coarse medieval coat of defense)

kriko

(device for raising and supporting a heavy object)

ĵako

(surface mounted connector)

ĵako

(female ended electrical connector)