I have seen both idioms used in practice. The definitions I found,
http://idioms.thefreedictionary.com/get+arms+around, and http://idioms.thefreedictionary.com/get+head+around
don't indicate much difference between the two and do not give any clue as to when one is more appropriate than the other.
The only significant distinction in the definitions is that "get one's head around" is mentioned as "informal", whereas "get one's arms around" is not.
- Is this distinction accurate?
- Are their others, both in term of meaning and usage?
Best Answer
I disagree that they are the same.
In my mind, "get one's head around" is about conceptual problems, whereas "get one's arms around" is about more physical things or actually "doing" stuff.
For example, I might say "I'm having problems getting my head around this task." meaning that I'm struggling to conceptually understand what I'm doing.
On the other hand, I might say "I'm having problems getting my arms around this task." meaning that I'm struggling to complete the actual task (but not because I don't understand).
As you can see, the distinction I draw is not a bright line in the sand, but I would say that it's consistent with how I've seen it used.