There are 17 words that start with 'mouse'.
| mouse | moused | 
| mouser | mouses | 
| mousey | mousers | 
| mousepad | mousebird | 
| mouselike | mousepads | 
| mousetail | mousetrap | 
| mousebirds | mousetails | 
| mousetraps | mousetrapped | 
| mousetrapping | |
Note: These 17 words that start with 'mouse' are found from the USA & Canada version of the tournament Scrabble word list.