early 14c., "end an argument," from Latin concludere "to shut up, enclose," from com- "together" (see com-) + -cludere, comb. form of claudere "to shut" (see close (v.)). Meaning "reach a mental conclusion, deduce" is from late 14c., a sense also in Latin. Related: Concluded; concluding.[conclude etymology, conclude origin, 英语词源]