A real receipt or something actually received in finance, and a radio callsign modifier in the military that specifies the commanding officer.

(uncountable) Reality, usually with the definite article.

(chiefly theology) relating to a person's acts or deeds; active, practical

Existing in reality, not just potentially; really acted or acting; occurring in fact.

(now rare) in action at the time being; now existing; current.

Used as intensifier to emphasise a following noun; exact, specific, very.