I have teenagers. Well, one so far. The other one just thinks she's a teenager. So I see a lot of commercials (especially this time of year) with teen idols screaming at me to "get their gear!!!" (OMG!). By gear, they mean clothing. And that got me thinking because gear used to have a totally different meaning, at least aboard ship.
Gear was never the things packed in a man's sea-chest. That was his dunnage (which in itself originally meant driftwood or spare wood left over from a project). Gear was the utility name for the rigging of any particular sail, square or fore-and-aft, which was used to make it fast to the mast's rigging. Generally, in older sailing ships, we are talking about rope. Being in gear meant that all was right; being out of gear meant that the rope in question was unfit for use and thus, so was it's sail.
As sailing ships improved and naturally became more complicated, the word gearing came into use. This indicated not just rope but the pulleys and blocks needed to make it hoist sail. Later, it came to refer to parts of an engine - wheels, shafts, pinions, etc. At some point these became simply gears, but that may or may not be borrowed from watchmaking which some etymologists believe adopted the term long before shipbuilding did.
The truly interesting thing is that all of these words in the English language came from the Anglo-Saxon root word geara which means clothing. So, as we have seen on innumerable Saturdays before, what goes around comes around. Now I'm off to get my gear on. I'll leave you to ponder that...