From WordNet (r) 2.0 (August 2003) [wn]:
euclidian
adj : relating to geometry as developed by Euclid; "Euclidian
geometry" [syn: euclidean]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Euclidian \Eu*clid"i*an\, n.
Related to Euclid, or to the geometry of Euclid.
[1913 Webster]
Euclidian space (Geom.), the kind of space to which the
axioms and definitions of Euclid, relative to straight
lines and parallel lines, apply; -- called also {flat
space}, and homaloidal space.
[1913 Webster]