We speak of a pair of shoes, a pair of socks, a pair of gloves. But why a pair of pants? 'He bought a new pair of pants.' 'Why, does he have four legs?' A pair of socks is two things, a pair of pants one. Raising to reflective awareness these little quirks of the mother tongue is a source of pleasure to some of us.
These are pronounced similarly: cowl, fowl, howl, jowl, owl, yowl. But 'bowl' is an exception. And note that each of the following is pronounced differently: blood, food, good. Blood is good food!
These are pronounced similarly: dour, hour, our, sour; but unlike 'four' and 'pour.' And 'tour' is pronounced differently still.
Addendum 5/28: A reader sends us here, where we read:
According to Michael Quinoin at World Wide Words, pants are a pair because, "before the days of modern tailoring, such garments, whether underwear or outerwear, were indeed made in two parts, one for each leg. The pieces were put on each leg separately and then wrapped and tied or belted at the waist (just like cowboys’ chaps). The plural usage persisted out of habit even after the garments had become physically one piece.
With a little stretching, the explanation can be made to fit 'pair of panties' despite their not having legs.
And that reminds me of the weighty question put to Bill Clinton: boxers or briefs? Instead of replying , as he should have, that that is not a question one asks the President of the United States, Bubba answered the question in a display of what could be called anti-gravitas. And of course thoughts of Clinton lead on quite naturally to thoughts of Monica Lewinksy and her thongs. 'Thong' and 'G-string' are two of the species of the genus 'panties.' Does one speak of a pair of thongs or a pair of G-strings? Do the English speak of a pair of knickers? If I am not mistaken knickers are what we call panties.