A credit expert's beginning to get the measure of land (4)
I believe the answer is:
Here is my best explanation:
'the measure of land' is the definition.
(I've seen this before)
'a credit expert's beginning to' is the subsidiary indication.
'credit' becomes 'cr'.
'beginning to' suggests taking the first letters.
The first letter of 'expert' is 'e'.
'get' is the link.
(Other definitions for acre that I've seen before include "A state of W Brazil", "Area of land", "Race (anag.)", "Crusaders battlefield, now in Israel", "Amount of land", "Old unit of area - old port", "BATTLE", "Levant sea port", "holy city" and "stretch of land".)