# Turing machine

[too r-ing, tyoo r-]

- a hypothetical device with a set of logical rules of computation: the concept is used in mathematical studies of the computability of numbers and in the mathematical theories of automata and computers.

## Origin of Turing machine^{}

after Alan M. Turing (1912–54), English mathematician, who described such a machine in 1936

Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

# Turing machine

- a hypothetical universal computing machine able to modify its original instructions by reading, erasing, or writing a new symbol on a moving tape of fixed length that acts as its program. The concept was instrumental in the early development of computer systems

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 turing machine

# Turing machine

### n.

1937, named for English mathematician and computer pioneer Alan M. Turing (1912-1954), who described such a device in 1936.

Online Etymology Dictionary, © 2010 Douglas Harper

# Turing machine

- An abstract model of a computing device, used in mathematical studies of computability. A Turing machine takes a tape with a string of symbols on it as an input, and can respond to a given symbol by changing its internal state, writing a new symbol on the tape, shifting the tape right or left to the next symbol, or halting. The inner state of the Turing machine is described by a finite state machine. It has been shown that if the answer to a computational problem can be computed in a finite amount of time, then there exists an abstract Turing machine that can compute it.

The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.