What's the difference between had and pluperfect?

Had

Definition:

• (imp. & p. p.) See Have.
• (imp. & p. p.) of Have

Example Sentences:

Pluperfect

Definition:

• (a.) More than perfect; past perfect; -- said of the tense which denotes that an action or event was completed at or before the time of another past action or event.
• (n.) The pluperfect tense; also, a verb in the pluperfect tense.

Example Sentences:

• (1) "You have never heard me say the BBC is a pluperfect organisation.