Runtime
Runtime is the period of time during which a program is running, executing the specific instructions that make up the software.
Runtime errors are common types of errors in software development. A runtime error is any error a program has while it is running.
Runtime Enviornment
The runtime environment is the infrastructure required to implement features in the language itself. This can include functions for optimization, memory management, debugging, and input/output. Runtimes make software development easier for engineers by making these functions more accessible.