Imperial unit of length (4)
'imperial unit of length' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for inch that I've seen before include "One of a 2 down in a foot" , "... or not so long < , Celtic island" , "0.0254 metre" , "Twenty five point four millimetres" , "0.08333 of a foot" .)
(Other definitions for foot that I've seen before include "Imperial distance" , "Twelve inches" , "support" , "12 inches" , "Metrical unit; pay (a bill)" .)
'imperial unit of length' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for yard that I've seen before include "Sail support" , "compound" , "Three feet out the back" , "Enclosure by house" , "Three feet - enclosed area" .)