procession vs motorcade

procession and motorcade both are nouns.

Word	Noun	Adjective	Verb	Adverb
procession	Yes	No	No	No
motorcade	Yes	No	No	No

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

procession: the group action of a collection of people or animals or vehicles moving ahead in more or less regular formation
motorcade: a procession of people traveling in motor cars

Other hyponyms of procession include convoy, caravan, train, wagon train, cavalcade, march, parade, cortege, recession, recessional.

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