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This article contains a list of commonly-used terms on the Day of Code, for reference.

Code languages


HTML stands for Hyper Text Markup Language. It is a way of providing structure to content.


We have chosen to use Ruby because it is an elegant language. You’ll know the seminal work on writing, Strunk and White’s “The Elements of Style”. William Strunk, Jr. would be delighted with Ruby:

Omit needless words.

Vigorous writing is concise. A sentence should contain no unnecessary words, a paragraph no unnecessary sentences, for the same reason that a drawing should have no unnecessary lines and a machine no unnecessary parts. This requires not that the writer make all his sentences short, or that he avoid all detail and treat his subjects only in outline, but that every word tell.

Strunk and White, The Elements of Style, 1918

As computing power has increased over the last few decades, we can have programming languages optimised for humans, not computers. Computers are powerful enough nowadays to allow Ruby methods to be written in clear English, which take longer to process than some terse machine code, but makes for a far more enjoyable coding experience, because Ruby is readable. Book.all, for example, means “get all the books”.

Code libraries


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Command prompt

Windows-specific command line interface (CLI) software. Also referred to as the “command line”.


Mac-specific command line interface (CLI) software, in which you can type commands directly to Unix, the underlying operating system of OS X. Also referred to as the “command line”.

Code organisation terms


Also referred to as “repos”, you can think of repositories as project folders, often versioned with a tool called Git. Github is a repository hosting service.