It's fine to be forgetful of maths that you're not actively using. (I am speaking as a mathematician.) It's also easier than ever to get a quick reminder or introduction, e.g. for this Google something like [what does e1 with ^ on the e mean], or [standard basis vector] from earlier in the sentence, or ask another AI.

I was never actually taught ê as unit vector notation. I did game development for years and am quite familiar with 3D math but a lot of formal math notation is very foreign to me.