There are 13 words that start with 'semil'.
| semilog | semillon | 
| semillons | semilunar | 
| semilethal | semiliquid | 
| semilethals | semiliquids | 
| semiliterate | semilustrous | 
| semilegendary | semiliterates | 
| semilogarithmic | |
Note: These 13 words that start with 'semil' are found from the USA & Canada version of the tournament Scrabble word list.