One second's worth of the computer's processing time, which is based on actual machine cycles used, not calendar time. See utility computing.
"CPU second." YourDictionary, n.d. Web. 10 June 2018. <http://www.yourdictionary.com/cpu-second>.
CPU second. (n.d.). Retrieved June 10th, 2018, from http://www.yourdictionary.com/cpu-second