Lambda

1. The name of the Greek letter Λ, λ, corresponding with the English letter L, l.
2. (Anat.) The point of junction of the sagittal and lambdoid sutures of the skull.
3. (Phys.) A subatomic particle carrying no charge, having a mass equal to 2183 times that of an electron; it decays rapidly, typically forming a nucleon and a pion.
Lambda moth (Zoöl.),
a moth so called from a mark on its wings, resembling the Greek letter lambda (Λ).