Ma'anar ƙamus na "post meridiem" (wanda aka fi sani da "p.m.") shine "bayan la'asar" ko "bayan tsakar rana." Yawancin lokaci ana amfani da shi don nuna lokacin rana a cikin tsarin agogo na sa'o'i 12 da ke biye da tsakar rana, daga 12:00 na dare. (na rana) zuwa 11:59 na dare (tsakar dare). Akasin haka, “ante meridiem” (wanda galibi ana taƙaita shi da “a.m.”) yana nuna lokaci daga tsakar dare zuwa tsakar rana a cikin tsarin agogo na awa 12.