- (Received Pronunciation) IPA(key): /siː ɛs ˈɛs/
- (General American) enPR: sē' ĕs' ĕsʹ, IPA(key): /ˌsi ˌɛs ˈɛs/
- Rhymes: -ɛs
- (aviation, travel) Initialism of . (a GDS code used on older types of airline keyboards)
- (historical, nautical, military) Initialism of . (The designation for a commissioned warship operated by the Confederate States Navy)
- (media, DVD) Initialism of .
- (medicine) Initialism of .
- (military, rocketry) NATO prefix-code for Chinese surface-to-surface missile systems developed by the People's Republic of China
- (nautical) Initialism of . (The designation for a survey ship operated by the Canadian Hydrographic Service)
- (Web design) Initialism of .
- (sports) Initialism of .
- (Web design): OOCSS
- ^ The Encyclopaedia of Sports Medicine: An IOC Medical Commission Publication, Endurance in Sport, John Wiley & Sons, 2008-04-30, ISBN 9780470694824: “During recent years a variety of non-invasive tests have been suggested. One of the most interesting is the method of critical swim speed (CSS), described by Wakayoshi et al. (1992)”