The term virus was first time coined by

The term virus was first time coined by Beijerinck.
Beijerinck, in 1898, was the first to call 'virus', the incitant of the tobacco mosaic.
Martinus Willem Beijerinck was a Dutch microbiologist and botanist who was one of the founders of virology and environmental microbiology.
He showed that the inoculant was able to migrate in an agar gel, therefore being an infectious soluble agent, or a 'contagium vivum fluidum' and definitively not a 'contagium fixum' as would be a bacteria.