Heisenbug

//ˈhaɪzənˌbʌɡ// noun

noun ·Rare ·Advanced level

Definitions

Noun
  1. 1
    A software bug which fails to manifest itself or manifests differently during debugging.

    "I recently encountered a particularly infuriating Heisenbug. A large program, when given a large input, was just mysteriously dying. Of course, I ran it under the debugger. The mystery deepened: the program returned quietly to the debugger."

  2. 2
    Alternative letter-case form of heisenbug. alt-of

Example

More examples

"I recently encountered a particularly infuriating Heisenbug. A large program, when given a large input, was just mysteriously dying. Of course, I ran it under the debugger. The mystery deepened: the program returned quietly to the debugger."

Etymology

(ca. 1983) Blend of Heisenberg + bug. Named for the Heisenberg uncertainty principle, which states very roughly that any attempt to measure the position of a subatomic particle will disrupt its movement, making it harder to predict.

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.