There are 711 13-letter words that start with 's'.
Note: These 711 13-letter words that start with 's' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with su, st, se, sp, sa, sh, sc, so, si, sl, sy, sn, sw, sk, sm, sq, sv, sf, sr, sj, sg.
2-letter words start with 's' (3)