There are 17 words that start with 'exon'.
| exon | exons | exonic |
| exonym | exonyms | exonumia |
| exonerate | exonumist | exonerated |
| exonerates | exonumists | exonerating |
| exoneration | exonerative | exonuclease |
| exonerations | exonucleases | |
Note: These 17 words that start with 'exon' are found from the USA & Canada version of the tournament Scrabble word list.