The word vector has many meanings.
- In epidemiology, a disease vector is an insect, animal or other organism which spreads disease indirectly.
- In mathematics and physics, a vector is a quantity with magnitude and direction. For example, an airplane has speed and a compass heading (e.g., 600 MPH, headed North). See vector space for further discussion of this topic.
- In computer science, the word has several meanings. The most common one in computer programming is that of an array—a data structure containing some number of similar items, which allows random access to its contents. This relates to the list of the components of a vector in physics, but it can consist of thousands of items in computer programs. Typical of this is the use in the C++ programming language Standard Template Library.
- A vector processor computer carries out operations on many elements of an array (that is, a vector) at the same time.
- Vector graphics are an obsolete form of computer graphics defined by line and shape primitives, as opposed to the modern bitmap graphics. In this sense, the word "vector" is related to the notion of a vector as a geometrical arrow.