There are 8 words that start with 'efferv'.
| effervesce | effervesced | 
| effervesces | effervescent | 
| effervescing | effervescence | 
| effervescences | effervescently | 
Note: These 8 words that start with 'efferv' are found from the USA & Canada version of the tournament Scrabble word list.