Precedence

Precedence is a binary relation between nodes in a tree structure, which is defined as in (i):

(i) Node A precedes node B iff A is to the left of B and A does not dominate B and B does not dominate A.

Example
in (ii) node B precedes nodes C, D and E, as well as the terminal nodes d and e. B does not precede b, since it dominates b. C, D and E do not precede B, since they are to the right of B. Also, A does not precede any of the other nodes since it dominates all of them.

(ii)		A / \ 	     /   \ 	     B     C              |    / \ |	 D  E              |   |   | b 	 d  e

Node D immediately precedes node E: there is no intervening node between D and E, i.e. there is no node X such that X is preceded by D and precedes E. Node B precedes E, but does not immediately precede it, since there is an intervening node: D, which precedes E and is preceded by B. Node C does not count as an intervening node between B and E: although it is preceded by B, it doesn't precede E, since it dominates it. Precedence (or linear order of constituents) has been believed to play a role in the conditions on coreference. This view has now largely been abandonned.

Links
Utrecht Lexicon of Linguistics