Lambdoid, from the Greek letter lambda (λ, lower case; Λ, uppercase); equivalent in sound to the "L" in English.

Something that is lambdoid in appearance typically approximates the shape of the upper case lambda, though the only use of the term in anatomy is for the inverted-U shaped lambdoid suture of the skull between the parietal and occipital bones. It was named by Galen in the 2nd century A.D.

Posterior view of skull.
Photo by C. Carpenter

"The lambda" is name given to the point of junction of the lambdoid and sagittal sutures.