ELI5 (Explain Like I'm Five)

ELI5 is an internet abbreviation for "Explain Like I'm Five," a request for an answer simple enough that a small child could follow it. The "five" refers to a five-year-old and is not literal; it signals that the asker wants a plain, jargon-free explanation of a complex topic rather than a technical or academic one.

The phrase took its modern shape on Reddit, where the community r/explainlikeimfive was created in 2011 as a friendly place to ask questions without fear of being mocked for not already knowing the answer. The subreddit grew into one of the largest on the platform, and "ELI5" spread far beyond it as shorthand across forums and chat. It matters to platform culture because it captures a deliberately welcoming norm in a setting often criticised for hostility to newcomers; a top-level rule of the community is that answers must be accessible, not literally aimed at children.