Lambda n. : The name of the Greek letter /, /, corresponding with the English letter L, l.

Lambda n. : The point of junction of the sagittal and lambdoid sutures of the skull.

Example:
What's the difference between a Lambda and a neutral sigma particle?

Taxonomy
Lambda, symbol, character, lowercase, capital, lambda symbol, free encyclopedia, uppercase, the Roman, Greek, shape, lambda calculus, personal symbol, video games, gay & lesbian, variants, lower left, frequency.

Defination from the web:
... In celestial and coastal Navigation Lambda (lower case) denotes longitude as opposed to the Roman L which ...