Semantics

moustache
Кћлины гусђрские усІ бІли лќхо подкрџчены квљрху. Kolya's hussar moustache was curled jauntily upward.
У моегћ дљдушки усІ бІли густІе, кђк у Стђлина на портрљтах, а у пђпы усІ бІли, кђк у Гќтлера, но перед войнћй ћн ќх сбрќл. My grandfather had a thick moustache like Stalin's in portraits, and my father had a moustache like Hitler's, but right before the war he shaved it off.
whiskers
У нђшего котђ седІе усІ. Our cat has grey whiskers.
This entry is concerned with the word усІ denoting hair on the upper lip of humans or whiskers on an animal. The singular form џс is used to describe the right or left half of a moustache. There are no specific expressions for whiskers on animals. Common sense will dictate which of the expressions can or cannot refer to animals.