Weight and mass comes to mind.
Weight isn't the vector quantity of mass. It's mass times acceleration, e.g. gravitational acceleration, g. In other words, it's a force.
It's also one of the places where US units really break down. Working with pound-force, pound-mass, and slugs is really easy to mess up if you have to work that way. You're often better converting to SI, doing whatever calculations you have to do, and then converting back at the end.
Yeh, in general the term is just misused and confusing.
Another example is "velocity" vs "speed"—what other vector quantity has two distinct names, one for the vector, another for the vector's magnitude? The acceleration doesn't, for example; and distance and displacement are two slightly different concepts that deserve two distinct names.