My American friends will be celebrating Thanksgiving tomorrow. Of course, as Latter-day Saints, we should focus especially on the "Thanksgiving" in the Bible. In the New Testament, the verb "to give thanks" is εὐχαριστέω. In 1 Cor 11:24-25, the apostle Paul writes:
And when he [Christ] had given thanks (εὐχαριστέω), he brake it, and said, take, eat: this is my body, which is broken for you: this do in remembrance of me. After the same manner also he took the cup, when he had supped, saying, This cup is the new testament in my blood: this do ye, as oft as ye drink it, in remembrance of me.
The most important "Thanksgiving" is that of the sacrament and the sacrificial remembrance (αναμνησις) we have therein of the atoning work of the Lord Jesus Christ.