This was originally posted as an answer in the How to suggest tag synonyms? question, but given my uncertainty in what synonym to suggest and the nature of their relationship, comment suggested it might be better as its own question.
I just noticed a new pair of candidates for tag synonyms that I'm not sure how to handle or if anything at all should be done:
One came first, one's American, one's Esri... Many search results list one first with the other in parentheses after. Different softwares call the tool that does the same thing (I think) one or the other. In terms of GIS and the questions, I'm not really seeing a difference between the two (please, correct me if I'm wrong) so it seems silly to have both separately. The wording in the Wikipedia article on Voronoi diagram would seem to suggest that Voronoi is more generic and Thiessen more specific to geophysics/spatial contexts - for whatever that's worth.
I'm wondering if maybe voronoi-thiessen-polygons might be the answer to which both get made a synonym.
Then again, there's also the term Delaunay Triangulation, which currently has no tag.
A related technical discussion on GIS SE is the following: