Crossword Genius

I'm grateful after unwrapping some yarn, say (4)

Ross

I believe the answer is:

hank

I'm a little stuck... Click here to teach me more about this clue!

'yarn say' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps you can see an association between them that I don't see?

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for hank that I've seen before include "Coil of wool for American Henry" , "-- Marvin, guitarist" , "Henry - coil of rope, wool or yarn" , "Skein (of wool, etc)" , "Loop of yarn" .)

I've seen this clue in The Times.
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