There are 50 13-letter words that start with 'hyper'.
Note: These 50 13-letter words that start with 'hyper' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with hyperp, hyperc, hyperm, hypers, hypere, hypert, hyperb, hypera, hyperi, hyperr, hypero, hyperv, hyperg, hyperl, hyperk, hyperf, hyperu, hyperh.
6-letter words start with 'hyper' (1)