being older or a senior; the first half of the year
This word has two distinct meanings. The first meaning refers to being older or having seniority. The second meaning, 'the first half of the year', is a rare, archaic usage that is not commonly encountered in modern Japanese. It may appear in historical or literary contexts.
He is older than me, so I should use polite language.
Older people have a wealth of experience.
The word is composed of 年 (year, age) and 強 (strong). The exact derivation is uncertain; it may have originally referred to someone strong in years, i.e., older. The second meaning 'first half of the year' is obscure and its origin is unclear.