lambdoid

/ˈlæm.dɔɪd/
adjective
  1. Shaped like the Greek letter lambda (Λ); having a triangular or Y-like form.
    • Archaeologists noted the lambdoid pattern carved into the ancient stone.
    • The lambdoid suture in the skull connects the parietal and occipital bones.
    • The lambdoid shape of the river delta was visible from the airplane.