HSK C7-9
Correct

纽

/ niǔ / 
Strokes

Definition

to turn/to wrench/button/nu (Greek letter Νν)

Example

As a Noun
handle; knob
As a Noun
button
As a Noun
bond; tie
As a Noun
key position; pivot
As a Noun
newly-grown fruit of melons, gourds, etc