gathering vs convening

gathering and convening both are nouns.

Word	Noun	Adjective	Verb	Adverb
gathering	Yes	No	No	No
convening	Yes	No	No	No

As nouns, convening is a hyponym of gathering; that is, convening is a word with a more specific, narrower meaning than gathering:

gathering (noun)	convening (noun)
the social act of assembling	the act of convening
the act of gathering something
sewing consisting of small folds or puckers made by pulling tight a thread in a line of stitching
a group of persons together in one place