'arboretum' originates from Latin, specifically the word 'arboretum', from 'arbor' meaning 'tree' and the suffix '-etum' meaning 'a place for planting or a collection of'.

'arboretum' was used in New/Modern Latin to denote a plantation or collection of trees and was borrowed into English largely in its Latin form, preserving the meaning.

Initially, it meant 'a plantation or collection of trees' in Latin, and over time it has retained this core meaning as a designated place for growing and studying trees.