In Japanese, Katamari (塊, Katamari?) means "clump" or "clod" and Damashii is the rendaku form of tamashii (魂, tamashii?) which means "soul" or "spirit". Therefore, the phrase approximates to "clump spirit" (in the same sense as "team spirit" or "school spirit", meaning "enthusiasm"; cf. the use of "damashii" in Yamato-damashii). The two kanji that form the name look nearly identical (sharing the same right-side radical) in a kind of visual alliteration. The name is officially transliterated as Katamari Damacy in most releases. In an interview with Dengeki Online, producer Keita Takahashi said when asked about the title, "It just popped into my head suddenly, and this is what it has been from the beginning."
Didn't know what Katamari meant, so I looked it up.
I did however remember hearing the word KAMATARI somewhere, so I looked it up too.
Kamatari
Kamatari (カマタリ, Kamatari?) is a small, seemingly one eyed, weasel holding a sickle with which it can cause a lot of destruction in a short amount of time. Its sickle is almost as large as itself. This mysterious weasel has only been seen twice for a few seconds after its summoning, once in the Sasuke Retrieval Arc, and once in the final filler arc. After it starts moving, it can't be seen by the unaided human eye. It is summoned using Temari's fan as a medium through Summoning: Quick Beheading Dance (口寄せ・斬り斬り舞, Kuchiyose: Kirikiri Mai?), after which it slices down all in its path with enough force to decimate an entire forest.
This weasel is a Kamaitachi (鎌鼬, "Sickle weasel"). This is the same name as Temari's Cutting Whirlwind Technique. It comes from the phenomenon wherein people claim to have been knocked down by a great gust of wind only to find they have been cut. Some say they have seen weasels wielding sickles that attack in groups knocking a person down and cutting them, even occasionally healing a wound so that they can attack again.
EDIT----Temari is from Naruto, for anyone who doesn't know.