topos

noun3

1. •
   A literary theme or motif; a rhetorical convention or formula.

   • The ritual of weighing the soul was an iconographic topos familiar to Christianity from the ceremony of the weighing of sins at the Last Judgement. — 2003
2. •
   A category that behaves like the category of sheaves of sets on a topological space (or, more generally, on a site).
3. •
   (slang) A toilet.