Cambrian explosion UK /ˈkam.bɹɪ.ən ɪkˈspləʊ.ʒən/US /ˈkæm.bɹi.ən ɛkˈsploʊ.ʒən/ noun1 •The rapid appearance of anything.There has been a Cambrian explosion of cryptocurrencies. formsCambrian explosions