There are 13 words that start with 'extend'.
| extend | extends |
| extended | extender |
| extenders | extending |
| extendable | extendedly |
| extendible | extendedness |
| extendability | extendednesses |
| extendabilities | |
Note: These 13 words that start with 'extend' are found from the USA & Canada version of the tournament Scrabble word list.