late 14c., "in equal shares," from equal (adj.) + -ly (2). Meaning "impartially" is from 1520s; that of "in an equal manner, uniformly" is from 1660s.
they were equally beautiful
they split their winnings equally
deal equally with rich and poor
equalitarianism
equality
equalization
equalize
equalizer
equally
equanimity
equanimous
equate
equation
equator