There are 12 words that start with 'osten'.
| ostensive | ostensory |
| ostensible | ostensibly |
| ostensoria | ostensively |
| ostensories | ostensorium |
| ostentation | ostentations |
| ostentatious | ostentatiously |
Note: These 12 words that start with 'osten' are found from the USA & Canada version of the tournament Scrabble word list.