Comment by gr4vityWall

Although not intuitive, it's common to call that the 'runtime' in the JS world, while V8 and JSC would be called 'JS engines'.

Deno used similar wording in a tutorial for creating your own JS runtime using Rust and V8 bindings: https://deno.com/blog/roll-your-own-javascript-runtime

IMO the tutorial is still cool nonetheless, it's a fun subject.