reminiscence vs remembering

reminiscence and remembering both are nouns.

Word	Noun	Adjective	Verb	Adverb
reminiscence	Yes	No	No	No
remembering	Yes	No	No	No

As nouns, remembering is a hypernym of reminiscence; that is, remembering is a word with a broader meaning than reminiscence:

reminiscence: the process of remembering (especially the process of recovering information by mental effort)
remembering: the cognitive processes whereby past experience is remembered

Other hypernyms of reminiscence include memory.

reminiscence (noun)	remembering (noun)
the process of remembering (especially the process of recovering information by mental effort)	the cognitive processes whereby past experience is remembered
a mental impression retained and recalled from the past