Safari is a swahili name(Swahili is spoken by people of the East-coast of Africa). It means a journey or an adventure. It could also mean a great undertaking. Steve must have known this from his many journeys.:)
I also suspect that this name came from some snark from Jobs against the web. If the browser is Safari, then logically, the WWW is a wild jungle. Even more relevant today, as Apple champions the idea of walled gardens in opposition to open application platforms.