The meaning of VIRAL is of, relating to, or caused by a virus. How to use viral in a sentence. Viral infections are illnesses you get from tiny organisms that use your cells to make more copies of themselves (viruses). Viral infections commonly cause respiratory and digestive illnesses, but viruses can also infect most other parts of your body. VIRAL definition: 1. caused by a virus: 2. used to describe something that quickly becomes very popular or well…. Learn more. The word Viral means "relating to viruses " (small infectious agents). It may also refer to: Memetic behavior likened that of a virus, for example: 1. Of, relating to, or caused by a virus. 2. Of or relating to the rapid propagation of information, ideas, or trends by means of social networks rather than conventional mass media: viral marketing. A viral film clip, story, or message is one that spreads quickly because people share it on social media and send it to each other. Sep 24, 2025 · viral (plural virals) (marketing) A video, image or text spread by "word of mouth" on the internet or by e-mail for humorous, political or marketing purposes. quotations Key points Viral meningitis is the most common type of meningitis. Most people get better on their own without treatment, but it can be very serious. Learn when to seek medical care for meningitis. used to describe a piece of information, a video, an image, etc. that is sent rapidly over the internet and seen by large numbers of people within a short time. Within 24 hours, the video went viral on YouTube and Facebook. Definition of viral adjective in Oxford Advanced Learner's Dictionary. pertaining to or involving the spreading of information and opinions about a product or service from person to person, especially on the internet or in emails. a clever viral ad. becoming very popular by circulating quickly from person to person, especially through the internet.