Czyja kolejka?

The English translation for this on CM is ‘Whose turn is it?’. Google translate suggests that ‘kolejka’ means queue, round or line. The Cambridge dictionary gives extra definitions of a ‘railway’ and a ‘switchback’ (on a rollercoaster).
The only sense I can make of it meaning ‘turn’, is ‘round’, as in ‘Whose round (e.g. of drinks) is it?’. Would it be similar in Polish? Can it also just mean ‘turn’, as in ‘Whose turn is it (e.g. to pay to game)?’. Thanks

In general, “kolej” is the word used to talk about order, especially when it comes to taking turns. For example, the most common/idiomatic way of saying “Your turn” is “Twoja kolej”. It is related to words such as “kolejność” (“order” / “sequence”) and “kolejny” (“next”).

“Kolejka” is the diminutive form of “kolej”. Because it’s diminutive, it will usually have “playful” connotations. So just like you suggested, it is mostly understood as a round of drinks or a turn in a board game (though we also have the more serious word “tura” for that).

So “kolejka” is a valid translation for “turn” here, and it seems to make sense in this particular sentence, though “Czyja kolej?” feels more likely if we’re not talking specifically about drinks.

A queue/line in a store is also “kolejka”. (“stać w kolejce” = “stand in a queue; queue for something”).

Finally, “kolej” can also mean “railway”. So if you’d like to say “to travel by rail”, you’d say “podróżować koleją”.

Both the “turn/queue” and “railway” meanings are etymologically related to the word “koło” (“circle” / “wheel”).