If you're willing to introduce the term "projection" then I think it's illustrative and has a good connection to other metaphorically identical connected projec

If you're willing to introduce the term "projection" then I think it's illustrative and has a good connection to other metaphorically identical connected projection concepts. "A mold is a projection function ranging over a span. As a projection function it converts any noun to the 'nearest' point in the span and is idempotent." (Edit: just realized that everyone under the sun whose had a dose of algebra is suggesting this term. I mean to go further when descrbing it as "taking nouns to the nearest thing in the span". A mathematician or sufficiently picky reader will ask what "nearest" means—and this may be exactly the right question—but the intuitive image may be more clear.)