Earlier quoted context omitted.
Seems hard to believe that an "engineer" with a degree in engineering or CS wouldn't know what is a unit vector.
Why? There are plenty of directions you can take through a CS degree that will never have you dealing with vectors at all. And subsequently there are plenty of CS heavy careers where you will never deal with it. What little I remember about vectors is from my high school maths classes, and in my 20 years of doing software engineering it's come up exactly once (for a GIS related project).
You are probably right about CS. I only have experience with engineering and wouldn't expect any engineer (i.e. a major in engineering) to not know that.
I wouldn't expect anyone working with machine learning to not know these concepts either.