axillaryPronunciation: /akˈsɪləri/Definition of axillary adjective 1 Anatomy relating to the armpit or a corresponding part:enlargement of the axillary lymph nodes 2 Botany in or growing from an axil:axillary budsOften contrasted with terminal. noun (also axillary feather) Ornithology feathers growing from the axilla. axillary in other Oxford dictionaries Definition of axillary in the US English dictionary