Today it means: Any extremely contagious filovirus infection of African origin that causes Ebola fever, spread through contact with bodily fluids or secretions of infected persons and by airborne particles, caused by the viruses in genus Ebolavirus. Full definition →
After Ebola river (area of discovery of type species) + virus. Reports conflict about who initially coined the name: either Karl Johnson of the American Centers for Disease Control or Belgian researchers.
Etymology from Wiktionary, CC BY-SA 4.0.