arbourarborn.

Etymology: This word has undergone great change of form and signification. Originally (h)erber , < Anglo-Norman (h)erber , Old French (h)erbier , a place covered with grass or herbage, a garden of herbs < Latin herbārium a collection of herbs, < herba grass, herb: see -arium suffix. Erber became arber by a change that was frequent with -er before a consonant (compare harb, arb, yarb, obsolete or dialect forms of herb itself; also arber, harbour, carve, starve, farm, etc., and the spoken forms of clerk, sergeant, Derby, Hertford, Cherwell); and arber was in 16th cent. written arbour, -or, in accordance with the common scribal interchange of -er, -our, -or (compare arbiter, -our, sailer, -our, -or). These phonetic and graphic changes were facilitated by the change of sense, as the word ceased to be associated with herb; the final acceptance of arbour, arbor, was probably aided by the natural tendency to connect it with Latin arbor tree, or Italian arborata bower. Hence, from c1550, there was a tendency to distinguish herbour and arbour, restricting the latter to senses 3, 5. Levins Manip. (1570) has ‘An Arboure, arboretum; an Herboure, viretum, herbaretum’; also, ‘Harboure, hospitium.’ This last word has also been supposed by some to have influenced the form of arbour; but of this there is no trace. Occasional instances of confusion between arbour and harbour are merely the mistakes of individuals.