For some time now, some of my on-line friends have advised me to provide a version of CassidySlangScam without the invective aimed at Cassidy and his supporters. In response to that advice, I am working on providing a glossary of the terms in Cassidy’s ludicrous book How The Irish Invented Slang with a short, simple and business-like explanation of why Cassidy’s version is wrong.
In his work of fanciful and fake etymologies, How The Irish Invented Slang, Daniel Cassidy claimed that the word joint, an old slang term for a house or bar or place in general, derives from Irish. The real experts are in agreement that the word seems to have originated in the English of Ireland, though not in the Irish language. As the Online Etymological Dictionary says:
Slang meaning of “place, building, establishment” (especially one where persons meet for shady activities) first recorded 1877, American English, from an earlier Anglo-Irish sense (1821), perhaps on the notion of a side-room, one “joined” to a main room.
For Cassidy, it has no connection with joining or adjoining. To him, it comes from the Irish word díonta, which according to Cassidy means:
Díon (pron. jinn), díonta, (pron. jínnta), n., a shelter, a roof, state of being wind and watertight; fig., a shelter of any kind, a house, shack, shanty, lean-to, “roof over your head”, tent. Díonta, (pron. jínnta), p.p. sheltered (from elements), protected. Díonta = Díon, n. (Ó Dónaill, 413)
This is not an accurate account of the meanings of díon/díonta. The word díon primarily means roof in Irish. It can also be used in a more general sense to mean protection. Thus uiscedhíonach means waterproof in Irish and tú féin a chur faoi dhíon duine means to place yourself under someone’s protection. However, it would not be used to mean a shelter or hide or hut, because there are better words for that, such as foscadh or scáthlán or dídean. Díonta is simply the plural of the noun díon and means rooves (or roofs if that is your preferred spelling). Díon is also a verb in Irish and díonta can be the past participle of that verb – i.e. roofed or protected. However, words do not cross easily in Irish between grammatical categories and díonta would not be used for a roofed place or sheltered place, as Cassidy implies, any more than you would say “I took shelter in a roofed” in English.
The word díonta is also pronounced jeenta, which doesn’t sound much like joint anyway.