Mega is a
unit prefix
A unit prefix is a specifier or mnemonic that is added to the beginning of a unit of measurement to indicate multiples or fractions of the units. Units of various order of magnitude, sizes are commonly formed by the use of such prefixes. The Metric ...
in
metric system
The metric system is a system of measurement that standardization, standardizes a set of base units and a nomenclature for describing relatively large and small quantities via decimal-based multiplicative unit prefixes. Though the rules gover ...
s of units denoting a factor of one million (10
6 or
). It has the unit symbol M. It was confirmed for use in the
International System of Units
The International System of Units, internationally known by the abbreviation SI (from French ), is the modern form of the metric system and the world's most widely used system of measurement. It is the only system of measurement with official s ...
(SI) in 1960. ''Mega'' comes from .
Common examples of usage
*
Megapixel
In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a Raster graphics, raster image, or the smallest addressable element in a dot matrix display device. In most digital display devices, p ...
: 1 million
pixel
In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a Raster graphics, raster image, or the smallest addressable element in a dot matrix display device. In most digital display devices, p ...
s in a digital camera
* One megatonne of
TNT equivalent
TNT equivalent is a convention for expressing energy, typically used to describe the energy released in an explosion. A ton of TNT equivalent is a unit of energy defined by convention to be (). It is the approximate energy released in the de ...
amounts to approx. 4
petajoule
The joule ( , or ; symbol: J) is the unit of energy in the International System of Units (SI). In terms of SI base units, one joule corresponds to one kilogram-metre, metre squared per second, second squared One joule is equal to the amount ...
s and is the approximate energy released on igniting one million tonnes of TNT. The unit is often used in measuring the explosive power of
nuclear weapon
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission or atomic bomb) or a combination of fission and fusion reactions (thermonuclear weapon), producing a nuclear exp ...
s.
*
Megahertz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base ...
: frequency of
electromagnetic radiation
In physics, electromagnetic radiation (EMR) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency or its inverse, wavelength ...
for radio and television broadcasting,
GSM
The Global System for Mobile Communications (GSM) is a family of standards to describe the protocols for second-generation (2G) digital cellular networks, as used by mobile devices such as mobile phones and Mobile broadband modem, mobile broadba ...
, etc. 1 MHz = 1,000,000
Hz.
*
Megabyte
The megabyte is a multiple of the unit byte for digital information. Its recommended unit symbol is MB. The unit prefix ''mega'' is a multiplier of (106) in the International System of Units (SI). Therefore, one megabyte is one million bytes ...
: unit of information equal to one million bytes (SI standard).
*
Megawatt
The watt (symbol: W) is the unit of Power (physics), power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantification (science), quantify the rate of Work ...
: equal to one million watts of power. It is commonly used to measure the output of
power plant
A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the electricity generation, generation of electric power. Power stations are generally connected to an electr ...
s, as well as the power consumption of
electric locomotive
An electric locomotive is a locomotive powered by electricity from overhead lines, a third rail or on-board energy storage such as a Battery (electricity), battery or a supercapacitor. Locomotives with on-board fuelled prime mover (locomotive), ...
s,
data center
A data center is a building, a dedicated space within a building, or a group of buildings used to house computer systems and associated components, such as telecommunications and storage systems.
Since IT operations are crucial for busines ...
s, and other entities that heavily consume electricity.
* Megadeath: (or megacorpse) is one million human deaths, usually used in reference to projected number of deaths from a
nuclear explosion
A nuclear explosion is an explosion that occurs as a result of the rapid release of energy from a high-speed nuclear reaction. The driving reaction may be nuclear fission or nuclear fusion or a multi-stage cascading combination of the two, th ...
. The term was used by scientists and thinkers who strategized likely outcomes of
all-out nuclear warfare.
Exponentiation
When units occur in
exponentiation
In mathematics, exponentiation, denoted , is an operation (mathematics), operation involving two numbers: the ''base'', , and the ''exponent'' or ''power'', . When is a positive integer, exponentiation corresponds to repeated multiplication ...
, such as in square and cubic forms, any multiples-prefix is considered part of the unit, and thus included in the exponentiation.
* 1 Mm
2 means one square
megametre
The following are examples of orders of magnitude for different lengths.
Overview
Detailed list
To help compare different orders of magnitude, the following list describes various lengths between 1.6 \times 10^ metres and 10^metres.
...
or the size of a
square
In geometry, a square is a regular polygon, regular quadrilateral. It has four straight sides of equal length and four equal angles. Squares are special cases of rectangles, which have four equal angles, and of rhombuses, which have four equal si ...
of by or , and not (10
6 m
2).
* 1 Mm
3 means one cubic
megametre
The following are examples of orders of magnitude for different lengths.
Overview
Detailed list
To help compare different orders of magnitude, the following list describes various lengths between 1.6 \times 10^ metres and 10^metres.
...
or the size of a
cube
A cube or regular hexahedron is a three-dimensional space, three-dimensional solid object in geometry, which is bounded by six congruent square (geometry), square faces, a type of polyhedron. It has twelve congruent edges and eight vertices. It i ...
of by by or 10
18 m
3, and not (10
6 m
3)
Computing
In some fields of
computing
Computing is any goal-oriented activity requiring, benefiting from, or creating computer, computing machinery. It includes the study and experimentation of algorithmic processes, and the development of both computer hardware, hardware and softw ...
, ''mega'' may sometimes denote (2
20) information units, for example, a megabyte, a megaword, but denotes (10
6) units of other quantities, for example, transfer rates: = .
In the case of
3½-inch floppy disks, sizes were given in megabytes of 1000KB or bytes.
The prefix ''
mebi-
A binary prefix is a unit prefix that indicates a multiple of a unit of measurement by an integer power of two. The most commonly used binary prefixes are kibi (symbol Ki, meaning ), mebi (), and gibi (). They are most often used in informat ...
'' has been suggested as a prefix for 2
20 to avoid ambiguity.
See also
*
Binary prefix
A binary prefix is a unit prefix that indicates a multiple of a unit of measurement by an integer power of two. The most commonly used binary prefixes are kibi (symbol Ki, meaning ), mebi (), and gibi (). They are most often used in inform ...
*
Mebibyte
The byte is a units of information, unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character (computing), character of text in a computer and for this ...
*
Order of magnitude
In a ratio scale based on powers of ten, the order of magnitude is a measure of the nearness of two figures. Two numbers are "within an order of magnitude" of each other if their ratio is between 1/10 and 10. In other words, the two numbers are ...
*
RKM code
The RKM code, also referred to as "letter and numeral code for resistance and capacitance values and tolerances", "letter and digit code for resistance and capacitance values and tolerances", or informally as "R notation" is a notation to speci ...
References
External links
{{wiktionary, mega-
BIPM website
SI prefixes
he:תחיליות במערכת היחידות הבינלאומית#מגה