avian

Avian comes from Latin avis, bird, one of the most productive roots in the English language's Latin inheritance. Avis is of ancient lineage: it connects to Sanskrit avi (bird), and the Proto-Indo-European root *h₂ewis, which appears to have meant 'a bird that flies high' — possibly the same root as Sanskrit vi (bird) and Old Prussian awi. From a single Latin noun came aviary (a place for birds), aviation (flying like a bird), aviate (to pilot an aircraft), and avifauna (the bird life of a region). When the H5N1 virus emerged, it was called avian influenza — a bird disease that threatened to become a human one.

The Romans used avis in augury — the reading of omens from bird behavior. The augur (from avis + garrire, to talk, or auspex, from avis + specere, to observe) watched birds for signs: their flight direction, their calls, their feeding patterns. An augur was literally a bird-reader. The word inaugurate, meaning to begin formally, comes from this practice: to inaugurate was originally to take the augury, to consult the birds before beginning a public undertaking. Every presidential inauguration carries the memory of Roman priests watching birds.

Aviation — flight itself — takes its name from birds. When the Wright brothers flew at Kitty Hawk in 1903, they were making literal the metaphor in their word: avian locomotion, human edition. The history of flight is largely the history of engineers studying birds: wing camber, aspect ratio, soaring behavior. The albatross inspired aircraft designers; vultures taught engineers about thermal soaring; the swift's wing shape influenced fighter jets. Avis is embedded in the technology it named.

Aviculture — the keeping and breeding of birds — carries the root. An aviary is an avis-house. The word peri-avian means around the bird; sub-avian means below the bird; extra-avian means outside the bird. Scientists studying the dinosaur-to-bird transition call the ancestral animals avian theropods and non-avian dinosaurs. The Latin word for bird has become the organizing concept for understanding 250 million years of vertebrate evolution. Avis means more than bird. It means the entire clade of living creatures that descended from a winged ancestor.