There are 11 15-letter words that start with 'hydr'.
| hydrobiological | hydrobiologists |
| hydrocephaluses | hydrocortisones |
| hydrodynamicist | hydromechanical |
| hydrometallurgy | hydrostatically |
| hydroxyapatites | hydroxylapatite |
| hydroxyprolines | |
Note: These 11 15-letter words that start with 'hydr' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with hydro, hydra, hydri.
5-letter words start with 'hydr' (2)