@MontereyJack,
In UK car driving terminology, overtaking definitely involves passing another vehicle or vehicles. Sections 267 to 269 of the "Highway Code", the official government driving guidance, specifically cover the topic of 'overtaking' on motorways (freeways). Section 267 says:
(Bear in mind we drive on the left; also passing on either side of slower vehicles is not allowed)
"Do not overtake unless you are sure it is safe and legal to do so. Overtake only on the right. You should
check your mirrors
take time to judge the speeds correctly
make sure that the lane you will be joining is sufficiently clear ahead and behind
take a quick sideways glance into the blind spot area to verify the position of a vehicle that may have disappeared from your view in the mirror
remember that traffic may be coming up behind you very quickly. Check all your mirrors carefully. Look out for motorcyclists. When it is safe to do so, signal in plenty of time, then move out
ensure you do not cut in on the vehicle you have overtaken
be especially careful at night and in poor visibility when it is harder to judge speed and distance."
There is an illegal practice, passing on the inside, which is sometimes called 'undertaking'.
Let us suppose I work in a sales team and I am in a race with my colleague to sell as many widgets as we can in a day.
10 AM: he has sold 50 widgets; I have sold 45. He is ahead of me.
11 AM: he has sold 65, I have sold 65 - I have caught him up!
12 noon: he has sold 80, I have sold 85... I have overtaken him.