There are 7 13-letter words that start with 'act'.
| actinometries | actinomorphic |
| actinomycetes | actinomycoses |
| actinomycosis | actinomycotic |
| actualization | |
Note: These 7 13-letter words that start with 'act' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with acti, actu, acto, acta, actr, acte, acts.
4-letter words start with 'act' (2)