Some of the verbage used may be difficult for someone who isn't verbose in 'techie' speak. Without trying to insult I try to explain the terms and phrases used for even a child's mind.
DNS Domain Name System. Each website and internet access point has a numerical address, but we as humans aren't really all that great at remembering numbers. So the Domain Name System was created to resolve alphanumeric text based names to the numbers we access the most, such as files and servers, for email, FTP (file transfer protocol), telnet, archie, or using the HyperText Transfer Protocol to access websites. When we can give our website an easy-to-remember name, such as Website Design Artist, it is much easier to remember that name, or brand, to return to it, especially when we are on a different computer and don't have it bookmarked. That domain name is actually access the website assigned internet numerical address because it resolves the name to that defined address using the DNS. This is why names and brands have become the web addresses we know, through the Domain Name System.
ICANN The Internet Corporation for Assigned Names & Numbers came into power as the administrator of the previous DNS (Domain Name System) as a governing body. Originally, it was known as the Internet Committee for Assigned Names & Numbers, but as corporate greed grew in the realization of its power over the internet, registries, registrations and registrants, so did the domain name regisration prices. You can't even get one of the new ICANN era .auto, .autos, or .car domain extension names for much less than $3,000.00 USD per year of registration, and ICANN has also implemented retail gouging for 'premium' names. This sort of racketeering has become a substantial burden to freelancers, entrepreneurs, small business and independent "mom & pop" businesses, which are left out in the cold, and hinders new "ICANN Era" top level domain name extensions development.
TLD Top Level Domain, usually referring to the extension, or the registry for the highest level of a domain name. As an example, the ".com" in WebsiteDesignArtist.com is the TLD under which this domain name is registered. The original TLD registries are .com, .net, .org, .int, .edu, .gov & .mil, which were grandfathered into the newer ICANN (Internet Corporation for Assigned Names & Numbers) DNS (Domain Name System).
gTLD The Global Top Level Domain, or Generic Top Level Domain is an incredibly over-done & over-priced expansion of the original TLD market, as assigned by ICANN. Generic/Global Top Level Domain name extensions (each with its own registry) are available to be registered by anyone, anywhere, though some new gTLDs (nTLDs or ngTLDs) will often have a target industry or geolocation.
ccTLD The Country Code Top Level Domain usually exists as the two letter abbreviation for a country. The ccTLD for the US is US (*.us). An exception was given for .EU since it is not a country, but it is a geographical location with boundries.
SLD Second Level Domain, which usually refers to second level extensions (registries) to ccTLDs. Examples include .co.uk, where the CO designation represents a commercial entity on the UK ccTLD. Other SLDs for the UK include NET (*.net.uk), ORG (*.org.uk) & ME (*.me.uk). Some countries have an elaborate list of SLDs to register for different industries. In the case of the UK, *.co.uk name registrations are supposed to be commercial entities connected to the UK, *.net.uk are supposed to be network systems and internet provider entities connected with the UK, *.org.uk is supposed to be for UK connected not-for-profit organizations, while *.me.uk names are intended for the private sector (UK citizens). In contrast, the US (*.us) ccTLD has no SLD layer.
nTLD or ngTLD The nTLD, or ngTLD designation refers specifically to the 'New TLD', the 'New Global TLD', or the 'Next Generation TLD' as ICANN balloons domain name registry availability with thousands of new extensions in order to cash in on corporate sponsorships and alleviate domain name registration space to make new domain name space available for registration. Unfortunately, this has had the opposite affect in most instances, as businesses wind-up rushing to register the company names, brands & trademarks they have already registered as .com, .net, .org, .info, etc... in order to protect their intellectual properties. This is not to say that the idea wasn't good at the start, but these new extension registries are almost always exorbitantly over-priced to the point of extortion for most small businesses, and the 'premium domain name registrations' program that ICANN has implemented to capitalize on good common names and relative keywords is the perfect example of the pure evil, corporate greed that ICANN now embodies.
Webmaster A webmaster is the person responsible for mastering the website. Duties will be quite different and ranging depending on the company, business, or person and what is required. Essentially, the webmaster is responsible for keeping the web presence up-to-date and online, setting up emails and keeping software & scripts updated on the web server/host, and is usually responsible for updating the website with content and new news, or correcting errors as they surface. This may or may not include other duties such as copy writing, promotion, marketing, UI design, script development, and/or website search optimization.
Hostmaster A hostmaster is the person responsible for domain name & website hosting support. Just as the webmaster is responsible for keeping the website up and available online, a hostmaster is responsible for keeping a domain name reachable, available and resolved within the DNS. A hostmaster can assist you with domain name technicalities, such as getting your domain name to resolve to your website by using specific nameservers.
Nameservers A nameservers is an internet connected server that assists a domain name to resolve to a certain assigned numerical internet address. When you register a domain name, you have to assign a couple or more nameservers to the domain. This nameserver than tells other nameservers where to find your domain name through the DNS (Domain Name System). Once this information is passed from nameserver to nameserver worldwide, that domain name will resolve to the website address specified, and if properly configured (usually very easily), your website will show-up for all of the free world on a global scale. Pleases note, however, that some oppressed countries cannot view the entire internet. Also note that there is a dark web that it is best to avoid.