A pigmented spot on the anterior margin of the wings of certain insects that is denser than the surrounding (typically transparent) parts of the wing and influences the motion of the wing membrane during flight.
Origin
Mid 19th century. From ptero- + stigma.
Definition of pterostigma in US English:
pterostigma
nounˌtɛrəˈstɪɡmə
Entomology
A pigmented spot on the anterior margin of the wings of certain insects that is denser than the surrounding (typically transparent) parts of the wing and influences the motion of the wing membrane during flight.