Lexical Environment
- Where something sits physically in the code you write
- ‘Lexical’ means ‘having to do with words or grammar’. A lexical environment exists in programming languages in which where you write something is important.
Execution Environment
- A wrapper to help manage the code that is running.
- There are lots of lexical environments. Which one is currently running is managed via execution contexts. It can contain things beyond what you’ve written in your code.
Object Definition
- A collection of name/value pairs
- The simplest definition when talking about Javascript.