xyl- combining form orxylo- Etymology: Latin, from Greek, from xylon; perhaps akin to Lithuanian šulas pillar, post, Old English sȳl — more at sile 1. a.: wood : woody < xylophone > < xyloma > b.: xylem 2. a.: xylene < xylic > < xyloquinone > b.: xylose < xylonic acid > < xyloketose > 3.xylo-, usually ital: having the stereochemical arrangement of atoms or groups found in xylose < l-xylo-ascorbic acid >