"state of being sick or suffering from a disease," Middle English siknesse, from Old English seocnes "sickness, disease; a particular malady;" see sick (adj.) and -ness. It formerly was synonymous with illness; in late 19c. sickness began to be restricted to nausea and other disturbances of the stomach, leaving illness as "a rather more elegant and less definite term" [Century Dictionary].
updated on September 29, 2022