Granny, perhaps, starts in silence (4)

I believe the answer is:

knot

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'granny perhaps' is the definition.
(granny is a kind of knot)

I don't understand the remainder of the clue.

(Other definitions for knot that I've seen before include "Bird; tie securely" , "Hard irregularity in timber - interlacing of cord" , "Tangled mass" , "Bend - one nautical mile per hour" , "Granny or reef, perhaps?" .)

I've seen this clue in the Evening Standard.

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