The official definition gives some high-level insight into the overall technology, but for the sake of completeness, it's worth digging a little deeper. WebAssembly's Core Specification is the official document to reference if you want to understand WebAssembly at a very granular level. If you're interested in learning about the characteristics of the runtime structure with regard to the execution environment, check out section 4: Execution. We won't cover that here, but understanding where the Core Specification fits in will help in establishing a complete definition of WebAssembly.