Related words are velocity, rapidity, and celerity which is proper velocity. "Celerity" means 'swiftness of speed'. A thousand fluid body positions give vigour, ardour and celerity. Proper velocity is sometimes referred to as celerity. The celerity difference between the highest and lowest sidebands is quite apparent to the listener. Santagati also serves on the board of directors of Revlon, Celerity Solutions, and CTC Communications. The given formula is for Stokes first definition of wave celerity. There were many similar descriptions of Butterfield's stage (celerity) wagons given by newspaper correspondents. Some BBS chat programs (i.e. Celerity BBS) also used a similar interface. Celerity Computing was founded in May 1983 by Steve Vallender, Nick Aneshansley and Andrew McCroklin. The Celerity 6000 was completed and released as the FPS Model 500 minisupercomputer. A brand-name, "Celerity", later became popular in place of mud (wagon). Celerity Computing Inc. was a San Diego, California vendor of Unix-based "supermini" computers. Celerity opened a charter school at the Church of the Redeemer two blocks away. Celerity shipped its first product, the C1200 Personal Workstation in November, 1984.