Length, an imperial measure, for cord round neck (7)
I believe the answer is:
lanyard
'cord round neck' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
I also know that 'neck' relates to this answer.
'length an imperial measure' is the wordplay.
'length' becomes 'l' (abbreviation in geometry).
'imperial measure' becomes 'yard' (yard is a kind of measure. I am not sure about the 'imperial' bit.).
'l'+'an'+'yard'='LANYARD'
'for' is the link.
Can you help me to learn more?
(Other definitions for lanyard that I've seen before include "Ribbon or cord around neck" , "Dawdler" , "Rope on ship's rigging" , "Cord with whistle attached" , "Neck cord holding whistle" .)