An igloo as a defensive position (10)
I believe the answer is:
blockhouse
This clue could be a double definition.
'an igloo' is the first definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'a defensive position' is the second definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.
'as' is the link.
Can you help me to learn more?
(Another definition for blockhouse that I've seen is " concrete shelter".)