The Free On-line Dictionary of Computing (30 December 2018):
A loop of code that executes without releasing
any resources to other programs or the operating system.
Consider the following pointless BASIC loop that counts
10 i = i + 1
20 GOTO 10
Run on a single-user system such as MS-DOS this will not
cause any problems. Run on a cooperative multitasking
operating system such as Windows 3, the system would appear
A pre-emptive multitasking operating system such as
UNIX or Windows NT would "steal" cycles away from
the program and continue to run other programs.
See also busy-wait and multitasking.