In the given sentence, the term that should be defined to clearly communicate ideas to a new student is "dialectic."
This is because "dialectic" refers to a specific method of discussion or reasoning that may not be familiar to all students, especially those new to the topic of writing composition. Defining this term would help them understand the approach being referenced in the context of writing.
Therefore, the correct response is:
A writer should define the term dialectic so students understand that the sentence is referring to a method of discussion.