The surrender or destruction of something prized or desirable for the
sake of something considered as having a higher or more pressing claim.
To surrender or give up, or permit injury or disadvantage to, for the sake of something else.
Forfeiture of something highly valued for the sake of one considered to have a greater value or claim.
Destruction or surrender of anything for the sake of something else;
devotion of some desirable object in behalf of a higher object, or to a
claim deemed more pressing; hence, also, the thing so devoted or given
up; as, the sacrifice of interest to pleasure, or of pleasure to
Hence, to destroy, surrender, or suffer to be lost, for the sake of
obtaining something; to give up in favor of a higher or more imperative
object or duty; to devote, with loss or suffering.
The act of losing or surrendering something as a penalty for a mistake or fault or failure to perform etc.
...the key here being that something good will come to those who sacrifice...