Defrag, short for Defragging, refers to the maintenance task that shifts the position or the layout of the files on the hard drive. For faster access, drives should get defragmented regularly.
The internet offers a variety of services including web or world wide web. The web is a way to access information over the internet.
URL shortening is a mechanism of translating a typically long URL into a shorter alternative that redirects to the same original URL.
".com" is the world's the most recognized top-level domains (TLDs) for urls. Some of the other commonly used TLDs are .org, .biz, .info, etc.
URL is an acronym for Universal Resource Locator. It acts as an address of a resource on the web, more accurately, on the internet. It can refer to the website, or some specific document, or an image.
HTTP status codes are standard response codes given by website servers. They help to identify the cause of the problem when a web page or other resource does not load correctly. 404 Not Found is the one of the most common status code.