Science, Tech, Math › Science Vector Definition in Science The Different Meanings of the Term Vector Share Flipboard Email Print This is an example of how vector addition works in math and physics. Encyclopaedia Britannica/UIG / Getty Images Science Chemistry Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated August 24, 2017 The term "vector" has different definitions in science, primarily depending whether the topic is math/physical science or medicine/biology. Vector Definition in Math and Physics In physical science and engineering, a vector is a geometric object which has both magnitude or length and direction. A vector is commonly represented by a line segment in a specific direction, indicated by an arrow. Vectors are typically used to describe physical quantities which have a directional quality in addition to a quantity that could be described by a single number with a unit. Also Known As: Euclidean vector, spatial vector, geometric vector, mathematical vector Examples: Velocity and force are vector quantities. In contrast, speed and distance are scalar quantities, which have magnitude but not direction. Vector Definition in Biology and Medicine In the biological sciences, the term vector refers to an organism that transmits a disease, parasite, or genetic information from one species to another. Examples: Mosquitoes are a vector of malaria. A virus may be used as a vector to insert genes into a bacterial cell.