Emily Dickinson Lexicon

HER-CU'LE-AN, a. [from Hercules. See Club of Hercules.]

1. Very great, difficult or dangerous; such as it would require the strength or courage of Hercules to encounter or accomplish; as, Herculean labor or task.
2. Having extraordinary strength and size; as, Herculean limbs.
3. Of extraordinary strength, force or power.