late 14c., "deduction or inference reached by reasoning, result of a discussion or examination," from Old French conclusion "conclusion, result, outcome," from Latin conclusionem (nominative conclusio), noun of action from past-participle stem of concludere "to shut up, enclose" (see conclude).
Also, from late 14c. "the end, termination, final part; closing passages of a speech or writing; final result, outcome." For foregone conclusion, see forego.
"indicating purpose," 1835, in Biblical philology, from Greek telikos "final," from telos "end, goal, result" (see telos).