There are 13 words that start with 'semico'.
| semicoma | semicolon | 
| semicomas | semicolons | 
| semicolony | semicolonial | 
| semicolonies | semiconductor | 
| semiconscious | semicommercial | 
| semiconducting | semiconductors | 
| semicolonialism | |
Note: These 13 words that start with 'semico' are found from the USA & Canada version of the tournament Scrabble word list.