â¢ SALTATION (noun) The noun SALTATION has 5 senses: 1. (geology) the leaping movement of sand or soil particles as they are transported in a fluid medium over an uneven surface. 2. a mutation that drastically changes the phenotype of an organism or species. 3. an abrupt transition.
A CAPTCHA as you may well know is one of those annoying âType in the letters you see in the image aboveâ things you see on many website signup pages or comment sections. A CAPTCHA image is designed so that a human can read it without difficulty while a computer is unable to.
Freebase(0.00 / 0 votes)Rate this definition: CAPTCHA. A CAPTCHA is a type of challenge-response test used in computing to determine whether or not the user is human. The term was coined in 2000 by Luis von Ahn, Manuel Blum, Nicholas J. Hopper of Carnegie Mellon University, and John Langford of IBM.