This is the 8938th most frequent Russian word.
пятнашке
"Пятнашке" refers to the game "tag" or "catch," where players chase and try to tag one another.
Here, 'пятнашке' refers to the game of tag, using the colloquial diminutive form to indicate familiarity or a casual reference.
Мы играли в пятнашке в парке после школы.
We played tag in the park after school.
In this case, 'пятнашке' indicates a score of fifteen, using colloquial language to refer to a grade in an informal way.
Он получил пятнашке на экзамене и был разочарован.
He got a fifteen on the exam and was disappointed.
Here, 'пятнашке' is used in the context of the tag game, implying the person who is 'it' and must chase others.