There are 13 words that start with 'mello'.
| mellow | mellows | mellowed | 
| mellower | mellowly | mellotron | 
| mellowest | mellowing | mellophone | 
| mellotrons | mellowness | mellophones | 
| mellownesses | ||
Note: These 13 words that start with 'mello' are found from the USA & Canada version of the tournament Scrabble word list.