This is the 4209th most frequent Russian word.
уку
The word "уку" does not appear to exist as a standard Russian word. It may be a typo or part of a larger context.
The term 'уку' here describes a small portion, focused on food.
Они поднесли уку хлеба к губам.
They brought a bit of bread to their lips.
In this sentence, 'уку' is figuratively used to denote a mark or indentation caused by an action.
Пчела оставила уку в моем яблоке.
The bee left a mark in my apple.
Here, 'уку' is used in the context of taking a bite of something.