Linearity is the property of a mathematical relationship or function which means that it can be graphically represented as a straight line.

Examples are the relationship of voltage and current across a resistor (Ohm's law), or the mass and weight of an object.

Proportionality implies linearity, but linearity does not imply proportionality.

Internet television (or online television) is the digital distribution of television content, such as TV shows, via the public Internet (which also carries other types of data), as opposed to dedicated terrestrial television via an over-the-air aerial system, cable television, and/or satellite television systems.

It is sometimes called web television, though this phrase is also used to describe the genre of TV shows broadcast only online.

Video on demand (display) (VOD) are systems which allow users to select and watch/listen to video or audio content such as movies and TV shows when they choose to, rather than having to watch at a specific broadcast time, which was the prevalent approach with over-the-air broadcasting during much of the 20th century.

IPTV technology is often used to bring video on demand to televisions and personal computers.

A television channel is a physical or virtual channel over which a television station or television network is distributed.

For example, in North America, "channel 2" refers to the broadcast or cable band of 54 to 60 MHz, with carrier frequencies of 55.25 MHz for NTSC analog video (VSB) and 59.75 MHz for analog audio (FM), or 55.31 MHz for digital ATSC (8VSB).

Channels may be shared by many different television stations or cable-distributed channels depending on the location and service provider.

A website is a collection of related web pages, including multimedia content, typically identified with a common domain name, and published on at least one web server.

A website may be accessible via a public Internet Protocol (IP) network, such as the Internet, or a private local area network (LAN), by referencing a uniform resource locator (URL) that identifies the site.