Calling a gun’s magazine a clip is a common mistake among new gun owners and shooters. And there are a lot of new gun owners right now. If you hear someone make this mistake in a gun shop or at the range, Rob Pincus urges you to refrain from pedantically correcting them about this terminology.
There will be opportunities for their firearms instructor to explain the difference to them and encourage them to use the two words properly. You, their fellow shooter, should let it go and say nothing about it. More new gun owners are a good thing and we should make them feel welcome in our community of defensive shooters, not embarrass them because they used a wrong word.