In relation to WordPress
Menus - Menus help you to structure the information architecture of the website so that visitors can navigate the website
Pages – static content – most likely to be used for content that you will not update regularly
Posts – These are entries listed in reverse chronological order – You are more likely to update this content on a regular basis
Categories – These are sections to which your posts belong ie. News, Blog, Events
Theme or Template - in relation to content management systems this is a series of files that controls how your content is displayed. Some themes can be used for free forever but sometimes it is best to pay a small amount to get your website looking good. We recommend Elegant Themes as a great supplied of paid for or premium themes
Plugin - a software component or “add on” that gives additional functionality to a website. This might be WooCommerce or a Form Plugin