The tengen (天元, "origin of heaven") is the name given to the center point of the Go board. On a 19x19 board this is the 10-10 point (K10).
See also :
Tengen is also the name given to one of the seven Japanese Big Titles (see Tengen - the title).
Tengen is also the name given to go club located in Jyväskylä, Finland: http://www.cc.jyu.fi/yhd/tengen/ . Jyväskylä is in the center of Finland. Tengen is the center of goban. Hence, go club of Jyväskylä got name Tengen.