on; on top; upon; first (of two parts); previous or last (week etc); upper; higher; above; previous; to climb; to go into; above; to go up; to attend (class or university); third tone of putonghua[cedict]
to act on; to affect; action; function; activity; impact; result; effect; purpose; intent; to play a role; corresponds to English -ity, -ism, -ization[cedict]