Karma is a Sanskrit term. It means action or deed. Any physical or mental action is Karma. Thinking is mental Karma. Karma is the sum total of our acts, both in the present life and in the preceding births.
Karma means not only action, but also the result of an action. There is a hidden power in Karma or action termed 'Adrishta' which brings in fruits of Karmas for the individual. The consequence of an action is really not a separate thing. It is a part of the action and cannot be divided from it.
Karma, according to Jaimini Rishi, is the performance of Agnihotra and other Vedic rituals.
According to the Gita, any action done with Nishkamya Bhava is Karma. Lord Krishna says: "Work incessantly. Your duty is to work but not to expect the fruits thereof." The central teaching of the Gita is non-attachment to work. Breathing, eating, seeing, hearing, thinking, etc., are all Karmas. Thinking is the real Karma. Raga-dvesha (likes and dislikes) constitute real Karma.
