noun

runtime

RUN-tyme

Runtime (noun) means the period during which a program is actually running, as opposed to the time when it is being written or prepared. Example: “The value is not known until runtime, because it depends on what the user types.”

noun

The period during which a program is actually running, as opposed to the time when it is being written or prepared.

"The value is not known until runtime, because it depends on what the user types."

"That mistake slipped past the checks and only showed up at runtime."

computing The supporting software that a program needs present on a machine in order to run, providing services such as memory management and access to the operating system.

"The application will not start unless the runtime is installed."

"Node.js is a runtime that lets JavaScript run outside a web browser."

The length of time a task, film or process takes from start to finish.

"The report has a runtime of about forty minutes on the older server."

How to Use Runtime

Learner’s notes

In plain EnglishThe time when a program is actually running, or the software it needs in order to run.

When to use it

Technical; also written as two words, run time, especially in the sense of duration.

Memory tip

Written as one word in computing and often as two, run time, when it simply means how long something takes.

Trace the full origin ↓

Easily confused with

compile time framework → interpreter → library →

Common pairings

at runtime runtime error runtime environment JavaScript runtime

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Fill the Gap

Can you complete this real example?

The value is not known until _____, because it depends on what the user types.

Etymology

A compound of run and time, originally written as two words in computing and later closed up.

Origin: English

Synonyms

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execution time run time runtime environment execution environment virtual machine duration running time elapsed time

Antonyms

compile time build time

Related Words

during period duration span virtual machine

Rhymes for runtime

time dime mime lime crime anime grime prime chime slime regime pastime

See all rhymes for runtime →

Frequently Asked Questions

What is the difference between runtime and compile time?

Compile time is when your code is being translated and checked before it runs, so mistakes such as bad syntax are caught then. Runtime is when the finished program is actually executing, so problems that depend on real data, files or user input appear at that point instead.

What is a runtime error?

It is a failure that happens while a program is running rather than while it is being built, such as trying to open a file that is not there or dividing by zero. The program may stop, or handle the problem if it was written to expect it.

Is a runtime the same as a framework?

No. A runtime provides the basic machinery a program needs to execute, while a framework is a set of code and conventions you build your own application inside. A framework normally runs on top of a runtime.

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