There are 39 15-letter words that start with 'micro'.
Note: These 39 15-letter words that start with 'micro' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with microp, microc, micros, microf, microb, microm, microt, microg, microa, microe, microi, microl, micron, microw, microv, microd, microh, micror, microo, microq.
6-letter words start with 'micro' (2)