# frequency

## Definitions

### General Science

• noun the number of repetitions per unit time of a complete waveform such as an electric or sound wave
• noun the probability of a item occurring in a sample
• noun the number of occurrences of something in a group or sample
• prefix one thousandth of a million millionth (10-15).

### Astronomy

• The number of waves of radiation of a particular wavelength passing a fixed point per second. The unit of frequency is the Hertz, one per second. The frequency of a signal multiplied by its wavelength equals its velocity, so that electromagnetic radiation of one metre wavelength must have a frequency of 300,000,000 hertz, or 300MHz, since all electromagnetic radiation has a velocity of 300,000 km per second in empty space. The same principle applies to other forms of wave energy like seismic waves and vibrations in interstellar gas clouds.

### Aviation

• noun the number of times or the rate at which something happens in a given period of time
• noun the number of repetitions per unit time of a complete waveform, as of an electric current frequency

### Cars & Driving

• noun in relation to a radio station, number of cycles per second expressed in hertz at which it broadcasts

### Computing

• noun a number of cycles or periods of a regular waveform that are repeated per second
• symbol the hexadecimal number equivalent to decimal number 15

### Construction

• A measure of oscillations per second, applied to the current or voltage of AC electrical circuits, sound waves or vibrating solid objects, and stated in hertz (HZ) or cycles per second (CPS).

### Economics

• The speed of the up and down movements of a fluctuating economic variable; that is, the number of times per unit of time that the variable completes a cycle of up and down movement. See destabilizing speculation.

### Electronics

• For a periodic phenomenon, the number of complete cycles per unit of time. When the unit of time is one second, the unit of frequency is the hertz. That is, 1 complete cycle per second is 1 Hz. Various multiples of hertz are frequently encountered in electronics, including kilo-hertz, megahertz, gigahertz, and so on. Examples of periodic phenomena include electromagnetic waves, sound waves, and AC. It is the reciprocal of period (2). Its symbol is f, or v, and its abbreviation is freq.
• symbolf

### Health Economics

• (written as Frequency)
The number of times an event occurs over a period. Not the same as 'being regular'.

### Information & Library Science

• noun a term used to describe the wavelength of broadcast transmissions

### Marketing

• noun the number of times an advertisement appears in a specific period
• noun the number of times a person sees an advertisement during a campaign

### Media Studies

• noun a measurement of radio waves, describing how quickly the waves are being transmitted. It determines where a station is found on a radio dial.
• noun the amount of exposure a topic is given in the media. A high frequency means that it appears often and prominently.
• abbreviationfreq.

### Medical

• noun the number of times something takes place in a given time
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