frons

Frons is a term used in anatomy and biology to denote the frontal surface of a head or a corresponding sclerite on the head. The word comes from the Latin frons, meaning forehead, and it is used across different scientific disciplines to identify a region located at the front or upper part of a head.

In human and vertebrate anatomy, the frons generally refers to the forehead region. In humans, the frontal bone forms much of this area and contains the frontal sinuses. The term appears in older or more formal anatomical descriptions to distinguish the forehead portion from other facial regions such as the brow, orbits, and nasal areas.

In entomology and other arthropod studies, frons denotes a specific plate on the dorsal surface of the head capsule. This frontal sclerite is typically positioned between the compound eyes and above the clypeus, though exact boundaries and terminology can vary among insect groups. The frons can be smooth, sculptured, or bristled, and its size, shape, and texture are often important diagnostic characters used in taxonomic descriptions and species identification.

Across fields, the precise boundaries and features of the frons are shaped by morphology and the particular classification system in use. In humans and other vertebrates, it emphasizes the forehead region; in insects, it is a distinct head plate that serves a key role in species-level taxonomy.