Engineering English
Assertion
Software Engineering · Last updated: July 30, 2026 · How this entry was written
Definition: An assertion is a boolean expression embedded in code that checks whether a specific condition holds true at runtime. It is used to validate assumptions and catch defects early during development or testing.
Example in context
“The developer added an assertion to verify that the sorted list length matches the input array length before returning.”
“Geliştirici, dönmeden önce sıralanmış listenin uzunluğunun giriş dizisi uzunluğuyla eşleştiğini doğrulamak için bir iddia ekledi.”
Where engineers use it
Assertions are embedded in code to document and enforce invariants, preconditions, postconditions, or expected states. Software engineers use them in both production code (for debugging) and test code to automatically check conditions and fail fast if something unexpected occurs.
Synonyms: assert
Practice: can you use “Assertion” at work?
You are debugging a function that calculates the factorial of a number. You want to ensure that the input is never negative during development. What language construct would you insert to check this condition automatically?
Show a model answer
“Add an assertion to ensure the user id is greater than zero before processing the request.”
“Assertion” in 21 languages
| English | Assertion |
|---|---|
| Turkish | iddia |
| French | assertion |
| German | Assertion |
| Spanish | aserción |
| Chinese | 断言 |
| Arabic | تأكيد |
| Portuguese | asserção |
| Russian | утверждение |
| Japanese | アサーション |
| Italian | asserzione |
| Vietnamese | khẳng định |
| Hindi | अभिकथन |
| Thai | การยืนยัน |
| Indonesian | asersi |
| Korean | 어서션 |
| Bengali | অ্যাসার্শন |
| Dutch | assertie |
| Swedish | påstående |
| Finnish | väittämä |
| Ukrainian | твердження |
Frequently asked questions
What does Assertion mean in engineering?
An assertion is a boolean expression embedded in code that checks whether a specific condition holds true at runtime. It is used to validate assumptions and catch defects early during development or testing. In Software Engineering, the term carries a usage-frequency rating of 10/10 in the Engineering English library.
How do you pronounce Assertion?
Assertion is pronounced /əˈsɜːrʃən/ (IPA). The Engineering English app plays audio for the term and checks your pronunciation with speech recognition.
How is Assertion used in a sentence?
Example from an engineering context: “The developer added an assertion to verify that the sorted list length matches the input array length before returning.”
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