preorder

Short definition from Wiktionary

Verb

1. 1
   To order (goods or services) in advance, before they are available.
2. 2
   To sort or arrange beforehand.

Noun

1. 1
   An order for goods or services placed in advance.
2. 2
   A binary relation that is reflexive and transitive.

Adjective

1. 1
   Such that, recursively, the root is visited before the left and right subtrees.