A CMS is an acronym for Content Management System. Often when a client requires a website to be created. they would like to be able to edit content themselves, or at the very least pay as little as possible for someone to edit content for them. The CMS of choice for Nixus is WordPress.
For example: Shopify is a type of content management system to manage product sets and products. WordPress can handle whatever you want it to.
Dev is short for developers, and licenses have the same meaning. When building a web project, if you coded everything yourself then a simple website would take months, a multi-vendor website would take years. Luckily we live in an age where a lot of coding has been done for existing technology and licensed out. The incentive for doing this is it is faster for us agencies to build web projects, and cheaper for the client.
For example: Shopify plugins are licensed to you and you pay per month to use it. WordPress acts the same way when resources are required or security is involved.