Execution Contexts and Lexical Environments

Syntax Parser

: A program that reads your code and determines what it does and If it grammar is valid

(character by character, using a set of rules for what's valid syntax and decide what is your intend)

Lexical Environment

: Where something sits physically in the code you write

'Lexical' means 'having to do with words or grammer'. 

A lexical environment exists in programming languages in which where you write something is important.

Execution Context

: 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.

Name/Value Pair

: A name which maps to a unique value

The name may be defined more than once, but only can have one value in any given context

That value may be more name/value pairs

Object

: A collection of name value pairs

The simplest definition when talking about Javascript

Hosting

: Setup memory space for variables(set equal to 'undefined') and functions

Single Threaded

: One command at a time     / Synchronous: One at a time

Invocation

: Running a function [In Javascript, by using ()]

Scope

: Where a variable is available in your code

And if it's truly the same variable, or a new copy