यज्ञ
yajña
Action done in a spirit of offering for a purpose larger than oneself. More than a ritual of pouring offerings into fire.
Yajña first means making an offering into fire. In the Gita its sense is far wider. The third chapter says that, except for action done as sacrifice, the world is bound by action, so one should act free of attachment for the sake of sacrifice (3.9).
In this light yajña is action that moves away from the self-centre and is done for a larger purpose, in a spirit of offering. The fourth chapter says that for one who acts for the sake of sacrifice, action melts away completely (4.23). The next verse sees the offering, the oblation, the fire and the one who offers as Brahman (4.24). When the giver, the thing given and the act of giving fold into one reality, there is no distance left between doer and deed for a bond to form across.
Common misreading: taking yajña to be only ritual or a fire ceremony.
Better sense: any action done in a spirit of offering.
The many kinds of sacrifice described in the later verses of chapter 4 are not the subject of this entry. To read further, see the topic Karma and Akarma.