The Idiom Attic - a collection of hundreds of English idioms, each one explained.
The meaning of "get your head around"
" Get your head around "
Meaning:
Understand something, especially something difficult to comprehend because it is complex or surprising.
Example:
Jill's mother had a baby girl after Jill had baby Jimmy, so Jimmy now has an auntie who is younger than him! That's weird. It took me a while to get my head around that.