There are 9 words that start with 'cosmop'.
| cosmopolis | cosmopolite | 
| cosmopolises | cosmopolitan | 
| cosmopolites | cosmopolitans | 
| cosmopolitism | cosmopolitisms | 
| cosmopolitanism | |
Note: These 9 words that start with 'cosmop' are found from the USA & Canada version of the tournament Scrabble word list.