Webster's Revised Unabridged Dictionary · 1913

Luncheon

Luncheon , noun

[Prov. English luncheon, lunchion, lunshin, a large lump of food, from lunch. See Lunch.]

1.
A lump of food. [Provincial English]
2.
A portion of food taken at any time except at a regular meal. [obsolescnet]
3.
A lunch, especially one organized by a group as a formal social gathering.

Luncheon , intransitive verb

To take luncheon. — Beaconsfield