fallacy

Etymology

From Middle English fallaci, fallace, fallas, from Old French fallace, from Latin fallacia (“deception, deceit”), from fallax (“deceptive, deceitful”), from fallere (“to deceive”).

noun

1. Deceptive or false appearance; that which misleads the eye or the mind.
2. (logic) An argument, or apparent argument, which professes to be decisive of the matter at issue, while in reality it is not; a specious argument.
   Baldridge also showed the "one molecule of blood," usually held to be the stimulus for attracting sharks, to be another common fallacy, since a molecule of blood does not exist. 1983, Richard Ellis, The Book of Sharks, Knopf, page 163