semiregular

alternative semi-regular

1. not comparableSomewhat regular; occasional.

   Although Lester must still see doctors on a semiregular basis for checkups, his health has returned to normal.

   2007 July 24, Bill Finley, “Victorious Night for Lester in His Return From Cancer”, in New York Times

   1 more example

   Hanging out after school with Grandpa Johnny on a semiregular basis got us both thinking the same thing: maybe we weren't the total losers everybody said we were.

   2017, James Patterson and Chris Grabenstein, Pottymouth and Stoopid, page 57

2. not comparablemathematicsWhose regular open sets form a base.

   A space is semiregular iff the regularly open sets (3D) form a base for the topology.[…]Every space X can be embedded in a semiregular space.

   1970, Stephen Willard, General Topology, published 2004, page 98

3. not comparablegeometryUniform (isogonal and isotoxal) with regular faces of two or more types, such that each vertex is surrounded by the same polygons in the same order.

   In a semiregular tessellation, there is an isometry of the plane carrying any vertex to any other vertex.

   1998, David A. Singer, Geometry: Plane and Fancy, page 35

   3 more examples

   It will be seen below that this semiregular polyhedron is of importance in its relationship to periodic minimal surfaces serving as a conceptual reference.

   1993, H. Terrones, A. L. MacKay, “The Geometry of Hypothetical Curved Graphite Structures”, in H. W. Kroto, J.E. Fischer, Deann Cox, editors, The Fullerenes, page 115

   While one of the semiregular polyhedra was mentioned by Plato, their first serious study is attributed to Archimedes.

   2003, Saul Stahl, Geometry from Euclid to Knots, published 2010, page 272

   One that we will consider here is the semiregular tessellation—a tessellation of two or more regular polygons that are arranged so that the same polygons appear in the same order around each vertex point. The tessellation at the left in Figure 9.38 is a semiregular tessellation because the two figures are a square and a regular octagon. The tessellation at the right in Figure 9.38 is not a semiregular tessellation because the two figures are a square and a nonregular octagon.[…]There are only eight possible semiregular tessellations.

   2011, Tom Bassarear, Mathematics for Elementary School Teachers, page 583