Meaning of left-branching

left-branch•ing

Pronunciation: (left'bran"ching, -brän"-), [key]
— adj. Ling.
  1. (of a grammatical construction) characterized by greater structural complexity in the position preceding the head, as the phrase my brother's friend's house; having most of the constituents on the left in a tree diagram (opposed to right-branching).
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.