This is the 2335th most frequent Russian word.
муку
"Flour" (a powder made by grinding grains).
Here, 'муку' refers to the ingredient 'flour' which is used in cooking.
Я купил муку для выпечки.
I bought flour for baking.
In this context, 'муку' again refers to 'flour' but describes its physical placement.
Муку осадило на поверхности стола.
Flour settled on the surface of the table.
The word 'муку' represents the feeling of the ingredient 'flour' during an activity.