Past perfect tense and Perfect tense

Past perfect tense noun - A perfective tense used to express action completed in the past.

Perfect tense and past perfect tense are semantically related. In some cases you can use "Perfect tense" instead a noun phrase "Past perfect tense".

Perfect tense noun - A tense of verbs used in describing action that has been completed (sometimes regarded as perfective aspect).

Past perfect tense and perfect tense are semantically related. Sometimes you can replace phrase "Past perfect tense" with "Perfect tense", this phrases are similar.