Scandinavian Defense is the chess opening characterized by the moves 1.e4 d5.
The Scandinavian Defence is an unbalancing, aggressive opening where Black immediately attacks White's e4-pawn. There is not much theory in this opening, and so Black can cut down on opening theory by playing this opening.
Black may recapture the pawn with his queen with 2...Qxd5, after 2.exd5, where his queen will have to move again.
Black may also attack the pawn with his knight with 2... Nf6, where White can gain space and Black will play in the fashion of the Alekhine defense, or White can hold onto the pawn with 3.c4, where Black usually offers a gambit of his c- or e-pawn.
For more information, refer to this website:https://en.wikipedia.org/wiki/Scandinavian_Defense