Polite copula and auxiliary verb used to end sentences politely. Equivalent to plain だ but in teineigo register. Also attaches to i-adjectives and negative forms to add politeness.
Literary/formal written form of だ/です, common in essays and reports.
Etymology
Derived from であります (de arimasu), a polite form of である (de aru). The exact historical contraction path is uncertain, but it became the standard polite copula in modern Japanese.
