IPA: /ˌɑːrˈbɔːr.i.ə.li/
KK: /ɑrˈbɔrɪəli/
In a way that relates to trees or living in trees.
The monkeys move arboreally, swinging from branch to branch.
Arboreally is formed from "arbor" (from Latin "arbor", meaning tree) and the suffix "-eally" (derived from the Latin suffix "-alis", meaning pertaining to). The word describes something that is related to or characteristic of trees.
Think of 'arbor' meaning tree, and remember that 'arboreally' refers to something that is related to trees.