adjournyoudaoicibaDictYouDict[adjourn 词源字典]
adjourn: [14] Adjourn originally meant ‘appoint a day for’, but over the centuries, such is human nature, it has come to be used for postponing, deferring, or suspending. It originated in the Old French phrase à jour nomé ‘to an appointed day’, from which the Old French verb ajourner derived. Jour ‘day’ came from late Latin diurnum, a noun formed from the adjective diurnus ‘daily’, which in turn was based on the noun diēs ‘day’.
=> diary, journal[adjourn etymology, adjourn origin, 英语词源]
adjourn (v.)youdaoicibaDictYouDict
early 14c., ajournen, "assign a day" (for convening or reconvening), from Old French ajourner (12c.) "meet" (at an appointed time), from the phrase à jorn "to a stated day" (à "to" + journ "day," from Latin diurnus "daily;" see diurnal).

The sense is to set a date for a re-meeting. Meaning "to close a meeting" (with or without intention to reconvene) is from early 15c. Meaning "to go in a body to another place" (1640s) is colloquial. The -d- was added 16c. but is unwarranted, as the compound is not from Latin. Related: Adjourned; adjourning.