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.
Certificates of Origin. When a vehicle is first manufactured, there is no title issued to identify ownership of the vehicle. Instead, manufacturers create documents known as certificates of origin to identify that the product is a newly manufactured vehicle. These certificates are sometimes called an MCO (manufacturer's certificate of origin), a COO (certificate of origin), or simply CO (certificate of origin). The certificates of origin are intended to serve as temporary ownership documents and are canceled at the time the vehicle is first titled.