There are 16 words that start with 'callo'.
| callow | callose |
| callous | calloses |
| callower | callosity |
| calloused | callouses |
| callously | callowest |
| callousing | callowness |
| callosities | callousness |
| callownesses | callousnesses |
Note: These 16 words that start with 'callo' are found from the USA & Canada version of the tournament Scrabble word list.