Relating to trees; of the nature of or belonging to trees; arboreal.
From Latin arbor (tree) with the suffix -ary (relating to or connected with). This follows the same pattern as library (relating to books), dietary (relating to diet), and military (relating to military forces).
The -ary suffix is super common for creating adjectives: primary, secondary, temporary, planetary. It's one of English's most useful word-building tools because it instantly turns a noun into a description. Add -ary to almost any noun and you've got an adjective.
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