In
go, a
keima is a stone that is displaced from another stone of the same color by the shape of a
knight's move from
chess - 1 line one way and 2 lines the other. Since in
japanese "Dia" means big, a Daigeima is a big version of a keima, so it means 3 lines in one way and 1 in the other. The k to g sound change is part of japanese rules for making compound words.
Japanese Go terms