Question

a word or phrase that modifies a word not included in the sentence is a(n) __________. misplaced modifier dangling modifier squinting modifier adjective

Answer 1

A word or phrase that modifies a word not included in the sentence is a dangling modifier. 
Here is an example:
Hungry, the leftover pizza was devoured.
You can see that the word hungry refers to us, but us is not included in the sentence. The way it is written, it would seem that hungry refers to pizza, which is wrong. 

Answer 2

The answer to the question above would be that a word or phrase that modifies a word not included in the sentence is a dangling modifier.

A modifier changes, alters, limits, or adds more information as regards something else in the sentence. Modifiers are considered dangling when it is not clear what is being modified.  The word or phrase modified is not clearly stated in the sentence. In fact, dangling modifers occur when the word or words they should modify have been omitted from the sentence.  Take A:

a) Hoping to excuse my lateness, the note was written and given to my boss.

"Hoping to excuse my lateness" is a dangling modifier.  The note cannot hope anything because it is an inanimate object, the words that "hoping to excuse my lateness" modify have been omitted.

Correction: Hoping to excuse my lateness, I wrote a note and gave it to my boss.