He·ro 2 
(hērō, hîrō) or He·ron (hērŏn′) First century AD.
(hērō, hîrō) or He·ron (hērŏn′) First century AD. Alexandrian scientist who invented many water-driven and steam-driven machines and devised a formula for deriving the area of a triangle from the lengths of its sides.
- unreeve
- unreflecting
- unreflectingly
- unreflective
- unreflectively
- unregenerable
- unregeneracy
- unregenerate
- unregenerately
- unrehearsed
- unrelenting
- unrelentingly
- unreliability
- unreliable
- unreliableness
- unreliably
- unrelieved
- unrelievedly
- unreligious
- unremarkable
- unremarkably
- unremarked
- unremitting
- unremittingly
- unremittingness