G - L
A GET request is one of the fundamental HTTP verbs.
Graphical User Interface
A graphical user interface (or GUI) is an interface to a program built with images, words and symbols.
The common name for an associative array. A named collection of key/value pairs.
Hello World Program
A Hello World program is a small program that simply prints something (usually "Hello world!") to the screen.
Hidden ID Field
A hidden unique ID field in an HTML form to protect against Cross-site Request Forgery (CSRF) vulnerabilities.
Symbols used to define the structure and format of an HTML document.
The Hypertext Markup Language.
An idempotent HTTP request is one that does not alter the state of a web application.
An 'idiom' is a commonly accepted preferred way of doing things. For example, Rubyists don't often use the for loop in Ruby, and instead opt to use the each method.
An IFRAME element is an HTML element that embeds another document inside the current document.
An interface is a system of interaction between components. It may refer to interaction between program components (an "application programming interface") or between a user and a program (a "graphical user interface" or "command line interface").
The IMG tag places an image in an HTML document.
An operator used to retrieve individual elements from a collection of elements, such as a hash or array.
Input/Output (commonly referred to as i/o or IO) is the data being input into the program (from file, network or keyboard) and the output generated by the program (written to file, network or screen).
To 'iterate' in Ruby and many other programming languages is to visit each element in a collection in turn. For instance, you may iterate over an array of numbers, visiting each number in the order they're stored in the array.
A client-side scripting language used in web browsers.
Any value associated with a key identifying it.
A keyword is a syntax element of Ruby that defines the basic functions of the language.
The word "lexical" is often used in discussions of scope. It refers to a variable or method's position within the text of the program.
A literal is an object that can be constructed using special syntax.