Responsive web design means that the website is designed to scale to all screen resolutions on all internet enabled devices. Responsive design is essential for all modern websites as 50% of people use a smartphone or tablet to acces the internet.
A user journey is the path a typical user might take to navigate a website. In the design phase the web designer will try to guide the user along a path that will allow them to reach their goal in the quickest and most intuative way possible.
Content Design is the process of designing content that is aestheticaly pleasing, easy to understand and informative. Well written copy, good image composition and displaying technical information in laymans terms are all part of Content Design.
Bootstrap is a modular responsive framework for building websites. It consists of a series of (CSS) LESS stylesheets a built in JQuery library and re-usable content blocks.
HTML stands for 'HyperText Markup Language' and is the standard coding language for building websites. HTML has just seen a massive version change with HTML5 adding much more graphical and multimedia functionality.
SEO stands for 'Search Engine Optimisation' and is the process of trying to get a website to rank well in search engine results when a user searches for your choses keywords or keyphrases.
A domain name is your address on the internet, for example the BBC's domain name is bbc.co.uk and Amazon's is amazon.co.uk / A new domain extension .uk has recently been launched, we will probaly see alot of major companies switching to this shorter extension in the future.
If a domain name is your address on the internet, Hosting is the home where your website files live, without hosting your website will not be accessible on the internet.