Karma is Sanskrit for "deed." In both Hinduism and Buddhism karma includes an individual's physical and mental actions which determine the consequences of the person's present life and sequential lives through rebirth. Karma is based upon the phenomena of cause and effect which denotes both action and reaction that extend through many lifetimes.
There are three types of karma: "agent-karma" which is concerned with the present cause and effect, and will influence future lives; "prarabdha-karma" which had already been caused and is in the process of being effected; and, "sanchita-karma" which has been accumulated but has not yet been effected.
Karma is normally thought of as a term used by eastern religions such as previously mentioned. But, in Plato's description of reincarnation he too touches on the theme of karma when saying the soul tends to become impure through bodily transmigrations. However, if the soul retains its pure state and does good acts it will return to its preexistent state, but if it continues to deteriorate by bad acts through bodily transmigrations it will go to a place of eternal damnation.