dismissyoudaoicibaDictYouDict[dismiss 词源字典]
dismiss: [15] Ultimately, dismiss and demise [16] are the same word: both come from Old French desmis or demis ‘sent away’. These in turn came from dismissus, the medieval descendant of Latin dīmissus, which was the past participle of dīmittere, a compound verb formed from dis- ‘away’ and mittere ‘send’. In the case of dismiss, English originally acquired the word, more logically, in the form dismit, based on the Latin infinitive, but in the late 15th century dismiss, in the past participial form dismissed modelled on the French past participle, began to replace it. Demise comes from Anglo-Norman *demise, which represents a nominal use of the feminine form of Old French demis.

It was originally a technical legal term signifying the transference of property or title, and only in the 18th century came to be used for the ‘death’ which often brought this about.
=> commit, demise, mission, transmit[dismiss etymology, dismiss origin, 英语词源]
dismiss (v.)youdaoicibaDictYouDict
early 15c., from Latin dimissus, past participle of dimittere "send away, send different ways; break up, discharge; renounce, abandon," from dis- "apart, away" (see dis-) + mittere "send, let go" (see mission). Prefix altered by analogy with many dis- verbs. Dismit, in the same sense, is attested from late 14c. Related: Dismissed; dismissing.