I'm noticing a trend... four of the past five Super Sentai series have had names beginning with "Go." Go-onger, Goseiger, Gokaiger, Go-Busters. I wonder if that's a nostalgia sort of thing, since the very first incarnation was Goranger. (And we've also had Goggle Five and GoGoV.) It could also be a pun on go being the Japanese word for "five," as in the number of Rangers, and on the English "go" and its connotations of action (as it was on GoGoV, and on Mach Go Go Go, aka Speed Racer).
It is a pun. The japanese love those. The same for the very original, Goranger. Their motto loosely translated was "Five People Together Goranger".