brown bag

Etymology
From the brown paper bag traditionally used to carry one's own lunch from home.

Noun

 * 1) A brown paper bag.
 * 2)  A short presentation or seminar on a given subject, especially one given at lunchtime.

Usage notes
Particularly in US English, and brown bag both appear in a variety of idiomatic expressions concerning butterfaces, people considered attractive apart from their face.

Verb

 * 1) To carry one's lunch from home, as in a bag, rather than purchase it from a cafeteria or restaurant.
 * 2) To consume alcohol in public from the bottle or can, while it is held concealed inside a brown paper bag, so as to avoid attention e.g. from the police.
 * 3)  To plant seed saved from one's own harvest, as opposed to buying new seed from a seed company.