There are 15 words that start with 'fissi'.
| fissile | fission |
| fissions | fissiped |
| fissility | fissional |
| fissioned | fissipeds |
| fissioning | fissilities |
| fissionable | fissiparous |
| fissionables | fissionability |
| fissiparousness | |
Note: These 15 words that start with 'fissi' are found from the USA & Canada version of the tournament Scrabble word list.