Means big, large
[1]
 
Parts Resembles a person with their arms does not mean 'arms', it is only used here to help you visualize the parts of the character as they relate to the memory hook. out to the side.
Memory hook Imagine a person describing something big by putting their arms out to show its size.
Combinations
ChineseliterallyEnglish
大人big personadult
Dialog
ChineseliterallyEnglish
人口大吗?person mouth big (question)Is the population large?
人口不大person mouth not big.The population is not large.
Self Test
 
[1] This Much 20040.jpg by user mliu92 from http://www.flickr.com/photos/mliu92/2129563135/, detail, under license: Attribution-Noncommercial-Share Alike 2.0 Generic