In total area length and line related (3,4)
I believe the answer is:
Here is my best explanation:
'in total' is the definition.
(I've seen this before)
'area length and line related' is the subsidiary indication.
'area' becomes 'a' (maths abbreviation).
'length' becomes 'l'.
'and' says to put letters next to each other.
'line' becomes 'l'.
'related' becomes 'told' (I've seen this before**).
(Other definitions for all told that I've seen before include "Everything taken into account", "sum", "To summarise", "In summary", "Everyone informed", "With everything or everyone taken into account", "Including everything", "Altogether", "Nothing missed out" and "Taking everything into account".)