There are 10 words that start with 'ester'.
| ester | esters | 
| esterase | esterify | 
| esterases | esterified | 
| esterifies | esterifying | 
| esterification | esterifications | 
Note: These 10 words that start with 'ester' are found from the USA & Canada version of the tournament Scrabble word list.