Haru - Spring
Natsu - Summer
Aki - Autumn
Fuyu - Winter
So the title means Spring, Summer, Autumn and Winter. So I suppose for brevity it can be translated as FOUR SEASONS which some googling reveals that in Japanese it is called Shi Ki. Ok, so there is a million ways to say the same thing in Japanese. Much like Chinese too when it comes to Four Seasons. I think I will stick with the literal translation for the time being. You will find this song in his album f.
An addendum. Found the partial lyrics from Masha Heart! The original singer was Shigeru Izumiya (still alive), a song from 1972! Can't find the original song in youtube though. The partially translated lyrics after Read More link thanks to Izumisano of Masha Heart and MashaPlus Info Forums, both links at the bottom of this page. I am too lazy to retype so I just took a screenshot of it. Again, very depressing lyrics and this was his audition song for Amuse audition!!