a square meal
noun phrase

- a satisfying meal that fills you and provides you with all the different types of food that your body needs in order to stay healthy

(Cambridge Dictionary)

Contrary to folk etymology, the expression square meal has nothing to do with the square plates the Royal Navy once used to feed its sailors. That’s actually a pity, because it makes for such an interesting explanation and it’s one that would impress family and friends.

The real, but rather mundane origin of this expression is the fact that the adjective "square" has long been used to mean proper, honest, fair. Thus a square meal is a decent one that provides sufficient nourishment. This phrase is American in origin and dates back to the late 19th century.

Square can be found in a variety of other phrases and idioms such as:

- square deal = a fair and honest transaction; fair treatment (I would recommend this shop if you are looking for a square deal on a new mobile phone)

- fair and square = completely fair(ly); justly; within the rules (We won the game fair and square, so don’t be such a sore loser)

- square away = to get someone or something arranged or properly taken care of (Let me get some paperwork squared away and then we’ll go to lunch)

- square up = to set something at right angles or to settle a bill or debt (If you go and get our coats, I’ll square up with the waiter)

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SYNONYMS

decent meal, full meal, substantial meal, three squares (three meals a day)

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SMUGGLE OWAD into today's conversation
say something like:

"Our company canteen ensures that I get at least one square meal a day."