Gröt means porridge, a warming food made from oats and water or milk and beloved in Sweden since Viking times.
There are many, many different kinds of gröt ranging from trollgröt or klappgröt (a lingonberry porridge eaten for dessert and whisked into a liquid), nävgröt (a substantial Värmland variant served with pork), julgröt (a dish similar to rice pudding and traditionally eaten on Christmas), tomtegröt (the porridge traditionally left out for the household gnome, naturally) and many others.
Other related words are grötslev or 'porridge ladle', a kitchen utensil specifically for the serving of porridge (usually made out of wood). Swedes are big fans of having specific tools for certain foods, with the cheese-slice and butter knife being two other examples.
There's also the adjective grötig (porridge-y, porridge-like), which describes something thick and unclear, and perhaps muddled - look out for Swedes describing the Danish language as grötig. Despite the popularity of porridge, it's not a compliment. And gröt itself can also be used in a metaphorical sense to mean 'mess' or 'muddle' or talk about something unclear.
How not to eat your gröt. via GIPHY
Because porridge itself has existed in Sweden for centuries, the Swedish language has long had words for porridge: grøter in early varieties of Swedish and grautr in Old Norse before that.
These words have their origins in the even older word greuna, which meant something like 'to coarsely grind'. This is also the root of other words such as gryta (stew) and grus (gravel/pebbles) in Swedish, but these were much more recent additions to the vocabulary than gröt.
Gröt also pops up in some Swedish idioms and proverbs. Het på gröten (literally 'hot on the porridge') is used to describe someone very eager about something or someone, often but not always with romantic or sexual connotations.. For example: Jonas är het på gröten för Anna (Jonas is keen on Anna).
Gå som katten kring het gröt (literally: 'to walk like the cat around hot porridge) is the Swedish equivalent of "to beat around the bush", meaning to take a long time to get to the point. In fact, the English language has its own feline version: 'to pussyfoot around something'. So if you say han gick inte som katten kring het gröt, it means 'he got straight to the point'.
And if you describe someone as grötmyndig (literally meaning something like 'of an age to make porridge' or 'authoritative in matters of porridge), it means 'haughty', 'pretentious' or 'loud-mouthed'. But this word actually doesn't have anything to do with porridge. It comes from Low German grootmündig, which became großmundig in today's German and literally means 'big-mouthed'.
Gröt är en god och nyttig mat
Porridge is a tasty and healthy food
Ska vi ha gröt till frukost?
Shall we have porridge for breakfast?