What does « Sacrifice / To slaughter » mean in the Quran?

And [recall] when We saved your forefathers from the people of Pharaoh, who afflicted you with the worst torment, slaughtering your [newborn] sons and keeping your females alive. And in that was a great trial from your Lord.

And [recall] when Moses said to his people, "Indeed, Allah commands you to slaughter a cow." They said, "Do you take us in ridicule?" He said, "I seek refuge in Allah from being among the ignorant."

He said, "He says, 'It is a cow neither trained to plow the earth nor to irrigate the field, one free from fault with no spot upon her.' " They said, "Now you have come with the truth." So they slaughtered her, but they could hardly do it.

Prohibited to you are dead animals, blood, the flesh of swine, and that which has been dedicated to other than Allah, and [those animals] killed by strangling or by a violent blow or by a head-long fall or by the goring of horns, and those from which a wild animal has eaten, except what you [are able to] slaughter [before its death], and those which are sacrificed on stone altars, and [prohibited is] that you seek decision through divining arrows. That is grave disobedience. This day those who disbelieve have despaired of [defeating] your religion; so fear them not, but fear Me. This day I have perfected for you your religion and completed My favor upon you and have approved for you Islam as religion. But whoever is forced by severe hunger with no inclination to sin - then indeed, Allah is Forgiving and Merciful.

And [recall, O Children of Israel], when Moses said to His people, "Remember the favor of Allah upon you when He saved you from the people of Pharaoh, who were afflicting you with the worst torment and were slaughtering your [newborn] sons and keeping your females alive. And in that was a great trial from your Lord.