a table: the furniture a household or its guests gather around to eat, and by extension the meal it holds or a table set apart for God.
At its simplest this is the ordinary table people sit around to eat. The Greek word literally pictures something four-footed, and that plain piece of furniture is where most of its uses live: the household table with its falling crumbs, the rich man's table that Lazarus longed to eat from, the table where Jesus shared his last meal.
From the furniture the word reaches naturally to what the furniture holds. A person's "table" can stand for their whole feast and security, and to sit "at my table" is to share in someone's honor and fellowship. The meal (δεῖπνον) is the event; the table is the standing place of belonging around it.
It also names tables set apart for God: the table that held the sacred bread in the sanctuary, and "the table of the Lord" that Paul sets against "the table of demons." To eat at such a table was to share in the worship it belonged to, which is why Paul treats it as the counterpart to the altar (θυσιαστήριον) where a sacrifice is offered up. The Hebrew Scriptures use one steady word for all of this (שׁלחן).