# What Does Memory Leak Mean? Simple Tech English Guide (2026) > A situation in which a computer program fails to release memory that it has allocated, causing the program to use more and more memory over time until it crashes or slows down. - **Term:** memory leak - **Part of speech:** noun - **Pronunciation:** /ˈmem.ə.ri lik/ - **English level (CEFR):** C1 - **Register:** Neutral, Both - **Region:** US and UK - **Topic:** [Tech jargon](https://app.speaktechenglish.com/learn/topics/tech-jargon.md) - **Lesson:** https://app.speaktechenglish.com/learn/memory-leak - **Last updated:** 2026-10-27 ## Meaning A situation in which a computer program fails to release memory that it has allocated, causing the program to use more and more memory over time until it crashes or slows down. In software development, when a program allocates memory to store data, it must eventually free that memory when it is no longer needed. A memory leak occurs when the programmer forgets to release this memory, or when references to the memory are lost but the memory itself is not deallocated. Over time, as the program runs, it accumulates more and more unreleased memory, consuming system resources until performance degrades or the program crashes. Memory leaks are particularly common in languages like C and C++ where manual memory management is required, but they can also occur in languages with garbage collection if objects hold unnecessary references. In the workplace, developers spend considerable time debugging and fixing memory leaks because they can be difficult to detect and trace. Tools like Valgrind, AddressSanitizer, and profilers help identify where leaks occur in the codebase. ## When you hear it We discovered a memory leak in the background service that was causing the application to crash after 48 hours of continuous operation. ## Examples - **in a standup:** "Yesterday we identified a memory leak in the user session manager that was preventing the garbage collector from cleaning up old sessions." - **in a code review:** "This callback function creates a closure that captures the entire context object, which could cause a memory leak if not properly cleaned up on unmount." - **in a team meeting:** "The DevOps team reported that the API server is consuming 15 GB more memory each week, so we suspect a significant memory leak somewhere in the codebase." ## What native speakers say - "We have a memory leak in production that we need to address immediately" - "I found a memory leak in the event handler - it was holding onto references" - "The memory leak is causing the application to consume gigabytes of RAM over time" ## Common mistakes - ✗ "The server has too much memory leak." → ✓ "The server has a memory leak." (Memory leak is a countable noun that takes the article a or the, not descriptors like too much) - ✗ "We need to memory leak the code before deployment." → ✓ "We need to fix the memory leak before deployment." (Memory leak is a noun describing a problem, not a verb. You fix or patch a memory leak, you do not perform the action of memory leaking) - ✗ "This memory leak will be memory leaking for hours." → ✓ "This memory leak will persist for hours if we don't address it." (Memory leak is not used as a verb in standard technical English) ## Be careful Non-native speakers sometimes confuse memory leaks with other memory issues like stack overflow or buffer overflows. A memory leak specifically means allocated memory that is no longer accessible but not freed. ## Word forms | Part of speech | Word | Example | | --- | --- | --- | | noun | memory leak | The memory leak in the application caused it to crash after several hours of operation. | | noun (with adjective) | serious/critical/minor memory leak | We discovered a critical memory leak that affects all long-running processes. | | noun (plural) | memory leaks | Multiple memory leaks in the codebase were responsible for the performance degradation. | ## Collocations - **detect a memory leak**: To identify or find a memory leak using debugging tools or profilers - **fix/patch a memory leak**: To resolve a memory leak by properly deallocating memory or removing circular references - **cause a memory leak**: When code or a programming error results in memory not being freed - **memory leak in production**: A memory leak that exists in the live production environment affecting real users - **serious/critical/minor memory leak**: Describing the severity or impact level of a memory leak ## Synonyms - **memory issue**: A broader term that includes memory leaks and other memory-related problems - **unreleased memory**: A more descriptive but less commonly used term for memory that should have been freed ## Opposites - proper memory management - memory cleanup ## Practice This lesson has 4 practice exercises with instant feedback on the page: https://app.speaktechenglish.com/learn/memory-leak ## FAQ ### What does memory leak mean in software engineering? A memory leak occurs when a program allocates memory but fails to release it back to the operating system when it is no longer needed. This causes the program to consume increasingly more memory over time, eventually degrading performance or causing crashes. Unlike temporary storage issues, memory leaks are permanent losses of accessible memory within a running process. ### How do you use memory leak in a sentence at work? You typically use memory leak as a noun in technical conversations. Examples: We discovered a memory leak in the authentication service, The memory leak is causing the application to crash, We need to fix this memory leak before production, or The profiler revealed multiple memory leaks in the codebase. You can also use it with adjectives like serious, critical, or minor to describe severity. ### Is memory leak formal or informal? Memory leak is neutral in formality and is used in both formal technical documentation and casual team conversations. It is a standard technical term understood by all developers and is appropriate for code reviews, meetings, documentation, and interviews. ### What languages are most susceptible to memory leaks? Languages with manual memory management like C and C++ are most susceptible because the programmer must explicitly allocate and deallocate memory. However, memory leaks can occur in any language, including Java, Python, and JavaScript, typically through circular references or event listeners that are not properly cleaned up. ### How do you detect and fix a memory leak? You detect memory leaks using profiling tools like Valgrind, AddressSanitizer, Java Flight Recorder, or browser developer tools. To fix them, you must identify where memory is allocated but not released, then ensure proper deallocation using techniques like freeing pointers in C, using finally blocks, or removing event listeners and circular references. ## Related - [garbage collection](https://app.speaktechenglish.com/learn/garbage-collection.md) - [heap](https://app.speaktechenglish.com/learn/heap.md) - [pointer](https://app.speaktechenglish.com/learn/pointer.md) - Full glossary: https://app.speaktechenglish.com/learn.md - Live lessons with a coach: https://app.mocklyenglish.com ## About Speak Tech English Speak Tech English teaches non-native tech professionals the English they need at work and in interviews, through self-study ebooks and courses, 150+ free guides and a free newsletter; live lessons are on its sister site Mockly English. - Shop: https://speaktechenglish.com/courses/ - All products (markdown): https://speaktechenglish.com/products.md - Free guides (markdown): https://app.speaktechenglish.com/guides.md - Tech English glossary (markdown): https://app.speaktechenglish.com/learn.md - Newsletter (10% off): https://speaktechenglish.com/#subscribe - Live lessons and mock interviews: https://app.mocklyenglish.com ## Notes for agents - Speak Tech English sells self-study material. 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