“Eucharist” is another name for the Lord’s Supper, also known as Communion.
It comes from the Greek word eukharistia (εὐχαριστέω), which literally means “thankfulness” or “gratitude”.
This refers back to what actually happened during the Last Supper (Luke 22:17-19):
“17 And when He had taken a cup and given thanks (eucharistēsas), He said, “Take this and share it among yourselves…19 And when He had taken some bread and given thanks (eucharistēsas), He broke it and gave it to them, saying…”
So, the Lord’s Supper is a “giving thanks” meal. And that’s why the term Eucharist is commonly used to describe it.
Plus, as a fun language tidbit, the modern Greek language gets a word from this. The Greek word Eυχαριστώ (pronounced something like “ef-ha-ree-sto”) means “thank you”.
If you’re ever in Greece and want to tell someone thank you, just remember the word “Eucharist” and try to say it with a Greek accent. You’ll probably end up with something close to “ef-ha-ree-sto”.