procession vs group action

procession and group action both are nouns.

Word	Noun	Adjective	Verb	Adverb
procession	Yes	No	No	No
group action	Yes	No	No	No

As nouns, group action is a hypernym of procession; that is, group action is a word with a broader meaning than procession:

procession: the group action of a collection of people or animals or vehicles moving ahead in more or less regular formation
group action: action taken by a group of people

Other hypernyms of procession include accumulation, aggregation, assemblage, collection.

procession (noun)	group action (noun)
the group action of a collection of people or animals or vehicles moving ahead in more or less regular formation	action taken by a group of people
the act of moving forward (as toward a goal)
(theology) the origination of the Holy Spirit at Pentecost