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megabyte

[meg-uh-bahyt]
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noun Computers.
  1. 220 (1,048,576) bytes.
  2. (loosely) one million bytes. Abbreviation: MB
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Origin of megabyte

First recorded in 1965–70; mega- + byte
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for megabyte

megabyte

noun
  1. computing 2 20 or 1 048 576 bytesAbbreviation: MB, mbyte See also mega- (def. 2)
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Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for megabyte

n.

1972, from mega- + byte.

The Sussex team has run the Forrester/Meadows models more than 1000 times on the UK's most powerful computer (the giant two-megabyte IBM 370/165 at Harwell). ["New Scientist," May 4, 1972]
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Online Etymology Dictionary, © 2010 Douglas Harper

megabyte in Science

megabyte

[mĕgə-bīt′]
  1. A unit of computer memory or data storage capacity equal to 1,048,576 bytes (1,024 kilobytes or 220 bytes).
  2. One million bytes.
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Usage: In computer science and industry usage, the prefix mega- often does not have its standard scientific meaning of 1,000,000, but refers instead to the power of two closest to 1,000,000, which is 220, or 1,048,576. The calculation of data storage capacity (measured in bytes) is based on powers of two because of the binary nature of bits (1 byte is 8, or 23, bits). Thus, a megabyte is 1,048,576 bytes, although it is also used less technically to refer to a million bytes. Other numerical prefixes are interpreted similarly. With data transmission rates (measured in bits per second), a bit is considered as a signal pulse, and calculations are generally based on powers of ten. Thus, a rate of one megabit per second is equal to one million bits per second. However, in certain technical contexts, megabit can also refer to 1,048,576 bits. Similarly, the prefix kilo- refers to 1,000 or 210 (1,024); giga- to 1,000,000,000 (one billion) or 230 (1,073,741,824); and tera- to 1,000,000,000,000 (one trillion) or 240 (1,099,511,627,776).
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

megabyte in Culture

megabyte

[(meg-uh-beyet)]

A unit of computer information: one million bytes.

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The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.