"Steve's class": origin of SC
The following is according to Nick Pippenger:

The relevant references are as follows.  Steve described NC as Nick's Class in his paper &quot;Deterministic CFL's Are Accepted Simultaneously in Polynomial Time and Log Squared Space&quot; (ACM STOC, 11 (1979) 338-345)  on SC, and I described SC as Steve's Class in my paper &quot;Simultaneous Resource Bounds'' (IEEE FOCS, 20 (1979) 307-311)  on NC.  But the names originated about a year-and-a-half earlier, when I visited the University of Toronto CS Department (January through June, 1978).  That's when the study of the two classes began, with Steve defining SC and me defining NC, and various people in the department (I think Allan Borodin was the first) using the two names.  The following fall, Steve submitted the paper cited above. I was on the program committee for that STOC, and not allowed to submit papers to it, so my paper appeared in the following FOCS conference.
Best wishes,
Nick