Noun
prototile (plural prototiles)
(geometry) Any of the minimal set of non-congruent shapes from which a larger set of shapes, some of which may be congruent, can be produced.
That is, the existence of a single-tile (monohedral) aperiodic prototile set is an open problem. Source: Internet
In the theory of tessellations, he devised the Conway criterion which describes rules for deciding if a prototile will tile the plane. Source: Internet