means A small invertebrate animal with a three-part body, six legs, and usually wings, belonging to the largest group in the animal kingdom.

from From Latin insectum, 'cut into,' the past participle of insecare (in- 'into' + secare 'to cut'). The Romans were describing the body's pinched, segmented look — those notches that divide head, thorax, and abdomen as if the creature had been scored with a knife. This was itself a translation of the Greek entomon, 'cut up,' the same root that gives us entomology. So every insect is, etymologically, a thing made of cut-apart pieces.