A contemporary quartz watch. Time perception is a field of study within psychology, cognitive linguistics and neuroscience that refers to the subjective experience of time, which is measured by someone's own perception of the duration of the indefinite and unfolding of events.
Cosine, a trigonometric function. COS cells, a cell line used by biologists. Carbonyl sulfide, (COS) a chemical compound. Cobalt sulfide, (CoS) a chemical compound. Class of service (CoS), a 3 bit field within a layer two Ethernet frame header defined by IEEE 802.1p. Class of service (COS), a configuration parameter in legacy telephone systems.
This applies to all CO safety alarms that meet UL 2034; however for passive indicators and system devices that meet UL 2075, UL refers to these as carbon monoxide detectors. CO is a colorless, tasteless and odorless compound produced by incomplete combustion of carbon containing materials.