There are 12 7-letter words that start with 'sem'.
| sematic | sememes | sememic | semidry | 
| semifit | semilog | semimat | seminal | 
| seminar | semipro | semiraw | semises | 
Note: These 12 7-letter words that start with 'sem' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with semi, sema, seme, semp, semb, semo.
4-letter words start with 'sem' (2)