a small usually single-celled asexual reproductive body produced by many nonflowering plants and fungi and some bacteria and protozoans and that are capable of developing into a new individual without sexual fusion; "a sexual spore is formed after the fusion of gametes"
(microbiology) single-celled or noncellular spherical or spiral or rod-shaped organisms lacking chlorophyll that reproduce by fission; important as pathogens and for biochemical properties; taxonomy is difficult; often considered plants
(virology) ultramicroscopic infectious agent that replicates itself only within cells of living hosts; many are pathogenic; a piece of nucleic acid (DNA or RNA) wrapped in a thin coat of protein
a software program capable of reproducing itself and usually capable of causing great harm to files or other programs on the same computer; "a true virus cannot spread to another computer without human assistance"
a harmful or corrupting agency; "bigotry is a virus that must not be allowed to spread"; "the virus of jealousy is latent in everyone"
a single undivided whole; "an idea is not a unit that can be moved from one brain to another"
an organization regarded as part of a larger social group; "the coach said the offensive unit did a good job"; "after the battle the soldier had trouble rejoining his unit"
a single undivided natural thing occurring in the composition of something else; "units of nucleic acids"
an individual or group or structure or other entity regarded as a structural or functional constituent of a whole; "the reduced the number of units and installations"; "the word is a basic linguistic unit"