Of, relating to, or characteristic of trees or tree-dwelling; having tree-like qualities.
From Latin arboreus (of trees) plus the English suffix -an (of or relating to). This creates another variant meaning the same concept as arboreal, like Mediterranean versus Mediterranean.
English has an embarrassment of riches when it comes to tree-related adjectives: arboreal, arborean, arboral, arborary, arboraceous. Having multiple terms lets scientists be precise about different contexts, but it also shows how language accumulates synonyms over time through different borrowing pathways.
Complete word intelligence in one call. Free tier — 50 lookups/day.