Kalmar "agerasia" ba a saba samunta a yawancin ƙamus, amma yawanci ana bayyana ta a matsayin yanayin ƙuruciyar ƙuruciya, duka a cikin kamanni da ɗabi'a, har ma a lokacin da ake yin shekaru a kan lokaci. Ana amfani da wannan kalmar sau da yawa a cikin mahallin neman rashin mutuwa ko sha'awar rage tsarin tsufa. A wasu lokuta, yana iya komawa ga imani cewa wasu ayyuka ko abubuwa na iya tsawaita rayuwar mutum.