Whether it matters...
It really depends.
An aviation example:
The levers that make the plane go faster (assuming attitude remains constant) could be throttles, power levers, or thrust levers. The correct term will vary by aircraft and propulsion system. (Edit: Forgot, but one airplane I flew called the primary lever a Power and Condition Lever, or PCL.)
Believe it or not, some people use the terms interchangeably, even though they really aren't.
If two pilots are shooting the bull, it probably won't matter.
If a pilot uses incorrect terminology with an examiner at a Biennial Flight Review, or during an airline periodic proficiency check, it might matter a lot more.
It can also affect instructor credibility with a new student, if the instructor is lax in his own terminology. (Edit: I might take an instructor or RO/SO a bit less seriously if he told me to load the clip to my HK...)
The situation determines whether the terminology is "a problem." That said, it's simpler to train oneself to just use correct terminology to the maximum extent, so one doesn't really have to think about one's situation quite so much.
Last edited by MLeake; May 13, 2013 at 05:02 PM.