- (immunology) A substance given to stimulate the body's production of antibodies and provide immunity against a disease, prepared from the agent that causes the disease, or a synthetic substitute.
- (context, marketing) A video, image or text spread by "word of mouth" on the internet or by e-mail for humor, humorous, political or marketing purposes; see viral marketing.
- 2002, Nik Lever, Flash Mx Games: ActionScript? for Artists, Focal Press, page 411,
- : Using the Flash ActiveX? control in this way allows you as a developer to create desktop characters, email virals and screensavers.
- 2003, Dave Chaffey, Total E-Mail Marketing, Elsevier, page 2,
- : Most virals are not seen as profiling and data collection exercises, since that would kill the impulse of forwarding to a friend.
- 2005, Russell Evans, Practical DV Filmmaking, Focal Press, page 289,
- : Music company virals are becoming commonplace as costs of promos force labels to reconsider how to target more directly to consumers.
- (virology) Of or relating to a virus (in the biological sense).
- (virology) Caused by a virus.
- (computing) Of the nature of a virus (in the computing sense); able to spread copies of itself to other computers.
- plant pathogens, of the order Viroidales, that consist of just a short section of RNA but without the protein coat typical of viruses
- The branch of microbiology that deals with the study of viruses and viral diseases.
- (context, mainly, _, medical) Of a disease or disease-causing agent, highly infectious, malignant, or deadly.
- hostile, Hostile to the point of being venomous; intensely acrimonious.
- The politicians were in their hatred of the president.
- (archaic) venom, Venom, as produced by a poisonous animal etc.
- (context, pathology, microbiology, virology) A submicroscopic infectious organism, now understood to be a non-cellular structure consisting of a core of DNA or RNA surrounded by a protein coat that requires a living cell to replicate — often causes disease in the host organism.
- 2001: Viruses are the smallest and most simplified forms of life. " Leslie Iversen, Drugs: A Very Short Introduction (Oxford 2001, p. 64)
- (computing) A computer virus.