Any of various eucalyptus trees having blueish leaves, especially Eucalyptus globulus. / (slang, offensive) A person of sub-Saharan African origin, referring to the blue coloring around their gumline.

plural of blue gum

The Australian eucalyptus, Eucalyptus globulus; a tall, straight tree, growing to 70 metres in height and 2 metres in trunk diameter.

plural of Tasmanian blue gum