One who poises or balances something. / The balancer of dipterous insects.

plural of derivationist

(Greek mythology) A king of Olympia; the son of Pelops and Hippodamia; and father of Pelopia and Aegisthus. He and his brother Atreus were exiled by their father for having murdered their half-brot...

Like a rock; stony; (figuratively) hard; callous