Kamehameha translated literally from phonetic Japanese to English means "Turtle Destruction Wave".
Kame (turtle) Hameha (destruction wave/blast)
This attack was created by Master Roshi during his material arts training. The Kamehameha wave sacrifices attack preparedness and speed in order to cause massive damage.
Instant Kamehameha: Seen only once in the Cell Games Saga, while Goku is fighting Complete Cell
, he is losing energy rapidly and pushes his remaining energy into one wave, at first it seems like he is going to destroy the planet and take Cell with him, however at the last minute he uses Instant Transmission (the technique of forming your physical body into mass a light and traveling to a location of somebody's Ki
to teleport directly in front of cell, thus canceling out Kamehameha's low rate of speed, and the time it takes to build up the attack
Big Bang Kamehameha: Gogeta's take on the Kamehameha and the Big Bang Attack, derived from Goku and Vegeta receptively.
In the first season, after Goku gets back from his training with North Kai, he uses the 4x Kaioken technique to increase the power of his wave, at the point where Vegeta tries to destroy the planet using his Galick Gun (a technique similar too, and is presumably as powerful if not moreso than a Kamehameha, this is hinted at because it takes a long time to gather the energy to fire this attack).
The Kamehameha wave was created by Master Roshi, a material arts trainer from the fictional anime series Dragonball.