H. P. Grice, "The most philosophically important Roman word!"

-- is res!

"Unfortunately, the etymology is dubious."

"Perhaps "res" comes from a root ra- of reor, ratus -- to reckon, calculate, believe, think, suppose, imagine, judge, deem, as in English 'ratify,' and 'reason.'

"I am reminded of German "ding;" English "thing," from "denken," to think; prop., that which is thought of."

"I am also reminded of "λόγος," Lid. and Scott, 9, a thing, object, being; a matter, affair, event, fact, circumstance, occurrence, deed, condition, case, etc.; and sometimes merely = something (cf.: causa, ratio, negotium)."