The term nameless usually refers to someone or something that doesn't have a name. Other than that it can refer to following:
In music
The Nameless, a Vancouver-based band formed in 2003
Orkest Zonder Naam (Nameless Orchestra), a Dutch orchestra of the catholic broadcasting corporation KRO
David Mathenge, a Kenyan musician using stage name Nameless
"The Nameless", a song by the band Slipknot off of their album,
"Nameless", a song by Avail from their 1996 album 4am Friday
Nameless is a band in Dayton, Ohio, led by Eric Ahoule
"Nameless", a song by defunct Irish band JJ72, from their album I To Sky (2002)
In fiction
Nameless, the protagonist of 2002 film Hero played by Jet Li
Nameless Detective, in a series of novels by Bill Pronzini
Nameless, Erast Petrovich, a pseudonym of Erast Fandorin, the protagonist of a series of detective stories by Boris Akunin
Nameless City, an ancient ruined city in H. P. Lovecraft's short story under the same title
The Nameless Nove
Source:
http://en.wikipedia.org/wiki/Nameless