First, define cat·a·calysm. Call it “a momentous and violent event marked by overwhelming upheaval and demolition; broadly: an event that brings great changes.” Then, recall that eerie poem you performed in the backyard as you swung on the tree-branch swing chanting “The permanent is ebbing.” Define the poem’s title, sea change (noun) as “archaic: a change brought about by the sea; a marked change; transformation.”