연세 (yeonse) means “age” | MotiTan Korean Dictionary

More examples

할머니는 연세가 많으셔도 목소리가 또렷하세요.hal meo ni neun yeon se ga ma neu syeo do mok sso ri ga tto ryeo ta se yo

Although my grandmother is elderly, her voice is clear.

A respectful label for someone's age when speaking about an older person.

살sal: Shows a person's age in years when placed after a number.
나이nai: The everyday term for the number of years a person has lived.

나이를 공손하게 이르는 말로, 주로 연장자에게 쓰이는 명사.na i reul kong son ha ge i reu neun mal lo chu ro yeon jang ja e ge sseu i neun myeong sa

Its Sino-Korean parts express the idea of years and age, while the whole word developed as a polite way to refer to an elder's age.

This is not a general replacement for age, since using it for a close friend of the same age can sound overly formal.