Top definition
Pronunciation: bee-chum

The phenomena that occurs when there are a few members of the opposite sex in a population (often in small schools or summer camps), as time continues prospective members of the opposite sex appear to become more attractive each day, often leading to regret and poor decisions.
Day 1 at camp
A: what do you think of Person X?
B: ehh, they're a 4, don't waste your time

A: agreed, no chance.

Day 15 at camp
A: I don't know what it is, but, person X looks much hotter.

B: it's that Beauchamp Phenomenon, don't fall for it!
by Ladle May 31, 2014
Happy St. Patties Day!