There are 23 7-letter words that start with 'sec'.
| secants | seceded | seceder | secedes | 
| secerns | seclude | seconal | seconde | 
| secondi | secondo | seconds | secpars | 
| secrecy | secrete | secrets | sectary | 
| sectile | section | sectors | secular | 
| secured | securer | secures | |
Note: These 23 7-letter words that start with 'sec' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with secu, secr, sect, seco, sece, secl, seca, secc, secp, secs.
4-letter words start with 'sec' (2)