1) Literally ‘cabbage yard’, although the evidence suggests that it may have been more generally ‘garden’.
The interest in the word is that it is dealt with very briefly in the OED and yet in Yorkshire was widely distributed and significant enough to give rise to a surname and several place-names: c.1270 Roger del Calgarth, Drax
1349 Thoma del Calgarth, Ripon: c.1290 cum quadam cultura que vocatur Kalegarth, Appletreewick
1346 ‘of the acres two ... lay in Hughcalgarth in the same field’, Kirby Knowle. As a word in the daily vocabulary it survived into the early eighteenth century at least: 1518 one place in Esholte with the callgarthe thereto belongynge
1575 j old calgarth spade, Burton in Bishopdale
1621 I will that Jane Metcalffe shall have ... one calgarth during her natural life, Askrigg
1693 the Great Calgarth or garden on one side of Hebden farm. See GRYD8-10.