Well, there are more than a pair of answers.
Why do we call it a pair of pants? #history #language #linguistics #
Funny Dumb Questions & Beyond! on the App Store
How Pants Should Fit
Usage and etymology of a pair of - English Language & Usage Stack Exchange
Why are underwear and pants always referred to as a pair? How many e-mails are sent every day? Do goldfish blink?
What's the Plural of Pants?
Topology of a pair of pants: The Hole Truth
A Trousers' or 'a Pair of Trousers'. Which Is Correct?
How to tailor a pair of jeans
Can someone explain me this meme? : r/EnglishLearning
Does 'pair of jeans' mean 1 or 2 jeans? - Quora
pants - Simple English Wiktionary
My Lifelong Quest for Pants That Actually Fit
Two Pairs of Pants?! - The Non-Consumer Advocate