adjective
not used before a noun US
older in age - usually + to
b - used chiefly in its abbreviated form Sr. to identify a father who has the same name as his son.
higher in standing or rank than another person in the same position
always used before a noun
of, relating to, or designed for older people
designed for or done by adults or people over a certain age
noun
plural -niors
[count] a person who is older than another person
a person who is of a higher rank than another person
US :a student in the final year of high school or college
chiefly US :senior citizen