english
1
general::
Find the basic underlying quality or cause of something. For example, He was determined to get to the bottom of the problem. [Late 1700s] Also see AT BOTTOM.
American Heritage Idioms
2
general::
Phrase(s): get to the bottom of something Fig. to get an understanding of the causes of something. • We must get to the bottom of this problem immediately. • There is clearly something wrong here, and I want to get to the bottom of it.
McGrawhill's American Idioms And Phrasal Verbs