“Gladius” was also the common Roman slang word for “penis”, so much so that the accompanying Latin word for a sword holder or scabbard, “vagina”, became the standard English word for a body part, losing its original meaning.
As mentioned below, a different sword is called Kukris. In Norwegian and Swedish, we have the word "kuk" that is a slang for the similarly named English "cock"
Maybe there is a connection there as well?