Any point of compass is singular, describing height and breadth (5)
I believe the answer is:
rhumb
'any point of compass' is the definition.
I can't tell whether this definition defines the answer.
'singular describing height and breadth' is the wordplay.
'singular' becomes 'rum' (synonyms).
'describing' indicates putting letters inside (describe can mean to form the outline of).
'height' becomes 'h'.
'and' says to put letters next to each other.
'breadth' becomes 'b' (this might be a standard abbreviation of which I'm unaware).
'rum' going around 'h' is 'rhum'.
'rhum'+'b'='RHUMB'
'is' is the link.
Can you help me to learn more?
(Other definitions for rhumb that I've seen before include "Any point of the compass - fixed line on a chart" , "Course following a uniform compass heading" .)