Real deckle edge paper is paper that isn't machine cut with with a straight edge so the edge has an uneven, feathery edge. Handmade paper, including in art and old documents, is often deckle edged. This above photo edge style, and the 1969 Topps Deckle Edge, are really pseudo-deckle edge or deckle edge-style because they were die-cut to have that style.
Real deckle edge paper:
