There are 11 11-letter words that start with 'sig'.
| sightlessly | sightliness | sightseeing | 
| sigmoidally | signalising | signalizing | 
| signalments | signatories | significant | 
| signifyings | signposting | |
Note: These 11 11-letter words that start with 'sig' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with sign, sigh, sigm, sigl, siga, sigi.
4-letter words start with 'sig' (2)