Definition of virus
1 archaic : venom 1
2 a : the causative agent of an infectious disease b : any of a large group of submicroscopic infective agents that are regarded either as extremely simple microorganisms or as extremely complex molecules, that typically contain a protein coat surrounding an RNA or DNA core of genetic material but no semipermeable membrane, that are capable of growth and multiplication only in living cells, and that cause various important diseases in humans, lower animals, or plants; also : filterable virus c : a disease or illness caused by a virus
3 : something that poisons the mind or soul <the force of this virus of prejudice — V. S. Waters>
4 : a computer program that is usually hidden within another seemingly innocuous program and that produces copies of itself and inserts them into other programs and usually performs a malicious action (as destroying data)
Examples of virus in a sentence
Is the illness caused by bacteria or a virus?
I think I have the virus that's going around this winter.
The software checks your hard drive for viruses.
Origin and Etymology of virus
Latin, venom, poisonous emanation; akin to Greek ios poison, Sanskrit viṣa; in senses 2 & 4, from New Latin, from Latin
First Known Use: 1599
VIRUS Defined for Kids
Definition of virus for Students
1 : a disease-causing agent that is too tiny to be seen by the ordinary microscope, that may be a living organism or may be a very special kind of protein molecule, and that can only multiply when inside the cell of an organism
2 : a disease caused by a virus
3 : a usually hidden computer program that causes harm by making copies of itself and inserting them into other programs
Medical Definition of virus
1a: the causative agent of an infectious diseaseb: any of a large group of submicroscopic, infective agents that are usually regarded as nonliving, extremely complex molecules or sometimes as very simple microorganisms, that typically contain a protein coat surrounding an RNA or DNA core of genetic material but no semipermeable membrane, that are capable of growth and multiplication only in living cells, and that cause various important diseases in humans, animals, and plants; also : filterable virusc: a disease caused by a virus
2: an antigenic but not infective material (as vaccine lymph) obtainable from a case of an infectious disease
Seen and Heard
What made you want to look up virus? Please tell us where you read or heard it (including the quote, if possible).