Epo en · NOUN Meanings (abbreviation, alt-of, initialism) Initialism of erythropoietin. alt of erythropoietin If you live or train for sports at high altitude where oxygen levels are lower, the production of Epo is stimulated and your blood contains more red cells. 2011, Terence Allen, Graham Cowling, The Cell: A Very Short Introduction, Oxford, page 86: Forms SpellingFeaturesLabelsSource Epos Number=Plur lexicographic