What does "insect" mean?

Additional senses

1. 2.(Zoöl.) Any small crustacean. In a wider sense, the word is often loosely applied to various small invertebrates.
2. 3.Fig.: Any small, trivial, or contemptible person or thing. Thomson. Insect powder,a powder used for the extermination of insects; esp., the powdered flowers of certain species of Pyrethrum, a genus now merged in Chrysanthemum. Called also Persian powder.
3. 4.Of or pertaining to an insect or insects.
4. 5.Like an insect; small; mean; ephemeral.