What is the etymology of "board" as found in "room and board"?

How did board come to be associated with meals?

I am referring to this definition of board:

• regular meals or the amount paid for them in a place of lodging (noun, Wiktionary)
• daily meals, especially as provided for pay (noun, reference.com)
• to furnish with meals, or with meals and lodging, especially for pay (verb, reference.com)

Board here means a dining table; its use is quite old.

The relevant meaning of board from the OED:

A table used for meals; now, always, a table spread for a repast. Chiefly poetical, exc. in certain phrases, esp. in association with bed to denote domestic relations [...] God's board: an old name of the Lord's table, or Communion table in a church. to begin the board: to take precedence at table.

The first citation of board as table is from around 1200 ("Mi bord is maked. Cumeð to borde."), and there are uses as late as the mid-1800s where board is used to mean "table" (without being part of the phrase "room and board"): "He looked at the banquet which was spread upon his board" (1862).

I was discussing this with my danish father, the danish word for table is Børd as in smorgasbørd, so we guessed it came from there. The danish word for lodgings is logi. We summised that a board game may have also been a derivative meaning table game.

Etymology Online suggests we have board from boarding, which itself appears to have taken the meaning "food" from the Old English notion of a table sometime around the 14th century.

All these posts are close but not quite there....it does indeed relate to a dining 'table' but the difference between a table and a board is that a board is just that: a plank, sometimes polished on one side, that rested on trestles and was used for eating meals. Tables have a surface that is fixed to legs.

In 16th-17th century England, the pay for farm labourers was set in law as "sixpence a day, BOARD and 8 pints of small ale" (weak ale about 1% alcohol - the only safe way to drink water). The board in question was their mid-day meal and was the only element of the pay that could be varied, so a landowner who wanted the best labourers would provide better food. Everyone would eat together, including the landowner who would sit at the head of the board in a chair (hence Chairman of the Board) whilst the others sat on benches. It was bad manners for men to have their hands out of sight (what could they be doing?) so hands were in view 'above board'. When not being used for meals, children could chalk or carve their games on the rough side of the board - 'board games'.

The sideboard is a similar piece of furniture at the side of the room on which other dishes would be laid before serving or to which empty serving dishes would be cleared. Bowls and dishes might also be stored here when not being used, but cutlery was never stored as each person had their own. This was usually a spoon, gifted at birth. Wealthy people had metal, the poor wood ('born with a silver spoon in his mouth').

Smaller boards were indeed used for serving food; usually square, they were hollowed out to hold the food like a bowl. They would often have a smaller hollow in the corner to hold a pinch of salt.

If you ever visit Mary Arden's Farm in Stratford on Avon (a tourist attraction that is part of the whole Shakespeare thing, Mary Arden being Will's mother) the guides, all of whom are in character dress and speech, will tell you all about 'board'. If you're lucky you'll be able to watch them have an authentic lunch.