(geology) Of or relating to the geologic eon from 2,500 Ma to 541.0±1.0 Ma.

plural of Mâcon

(medicine, colloquial) Pulse oximetry. / (medicine, colloquial) Pulse oximeter.

A suburban area in the Metropolitan Borough of Tameside, Greater Manchester, England (OS grid ref SJ9794). / A habitational surname from Old English.