"gear" = disk with teeth cut into it etc . plural = gears (more than one)
"gear" = equipment. Plural = "gear" being a collective noun. Other examples of collective nouns (words that are spelled and pronounced the same for both singular and plural) are; sheep, deer, information, equipment, and of course the most famous or infamous being the word "beer". Two sheep, three deer and four cows where in the field enjoying the nine beer the hikers had forgotten. Please don't take the above too seriously. It is interesting to watch the English language evolve (or devolve) as time goes on. I just wonder if the evolution of this language has accelerated somewhat due to the number of beer (beers) being consumed on a daily basis?