forumyoudaoicibaDictYouDict[forum 词源字典]
forum: [15] Originally Latin forum denoted an ‘out-of-doors place’ – it was related to forīs ‘outof- doors, outside’ and to forēs ‘door’, a distant cousin of English door. It came to be used for any outdoor open space or public place, and in particular for a market place (the most famous of which was the one in Rome, where public assemblies, tribunals, etc were held). Other English words from the same source are foreign, forest, and forensic ‘of legal proceedings’ [17] (from Latin forēnsis ‘of a forum as a place of public discussion’).
=> door, foreign, forensic, forest[forum etymology, forum origin, 英语词源]
forum (n.)youdaoicibaDictYouDict
mid-15c., "place of assembly in ancient Rome," from Latin forum "marketplace, open space, public place," apparently akin to foris, foras "out of doors, outside," from PIE root *dhwer- "door, doorway" (see door). Sense of "assembly, place for public discussion" first recorded 1680s.