There are 10 12-letter words that start with 'gas'.
| gasification | gastightness | gastrocnemii |
| gastronomies | gastronomist | gastroscopes |
| gastroscopic | gastrotrichs | gastrulating |
| gastrulation | ||
Note: These 10 12-letter words that start with 'gas' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with gast, gaso, gass, gash, gasi, gasp, gasc, gase, gask, gasl, gasa, gasb, gasm, gasw.
4-letter words start with 'gas' (3)