The Collaborative International Dictionary of English v.0.48:

Angio- \An"gi*o-\ ([a^]n"j[i^]*[-o]-). [Gr. 'aggei^on vessel
   receptacle.]
   A prefix, or combining form, in numerous compounds, usually
   relating to seed or blood vessels, or to something contained
   in, or covered by, a vessel.
   [1913 Webster]