There are 7 14-letter words that start with 'os'.
| oscillographic | osmoregulation |
| osmoregulatory | ostentatiously |
| osteoarthritic | osteoarthritis |
| osteosarcomata | |
Note: These 7 14-letter words that start with 'os' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with ost, osm, osc, oss, ose, osi, osn, osp, osa.
3-letter words start with 'os' (1)