1. A descriptive term for an act of killing an animal or person or surrendering a possession as an offering to a deity: Some ancient rituals required a sacrificial animal be brought to the altar just as the moon was to appear over the horizon.
2. Used in or connected with an act of giving up something one values for the sake of something that is considered to be of greater importance: Madeline Jason made a sacrificial commitment to give her entire estate to a university in memory of her son who had attended there and who had died in a hiking accident.