There are 17 words that start with 'arsen'.
| arseno | arsenal |
| arsenic | arsenals |
| arsenate | arsenics |
| arsenide | arsenite |
| arsenous | arsenates |
| arsenical | arsenides |
| arsenious | arsenites |
| arsenicals | arsenopyrite |
| arsenopyrites | |
Note: These 17 words that start with 'arsen' are found from the USA & Canada version of the tournament Scrabble word list.