older

adjective

Of greater age than another: elder, senior. See youth/age/maturity.

Definition: most senior
Antonyms: younger

Tutor's tip: An "elder" (a person with authority) statesman in the Senate is not necessarily "older" (comparative of old) than the other senators.

The adjective has 4 meanings:

Meaning #1: advanced in years; (`aged' is pronounced as two syllables)
  Synonyms: aged, elderly, senior

Meaning #2: older brother or sister
  Synonyms: big, elder

Meaning #3: used of the older of two persons of the same name especially used to distinguish a father from his son
  Synonyms: elder, sr.

Meaning #4: old in experience
  Synonym: old