A few tips / definitions / explanations. (Disclaimer: I may be wrong, but my understanding has been "good enough" to get me through the day, keep me gainfully employed and my hardware generally running well.)
The Linux operating system consists of one major component known as the kernel plus several "standard" applications that give you a bare-bones, "well, I can type something and it responds" interface -- somewhat similar to the old, old, old computers that, when you turned them on, you would get the BASIC programming language and nothing more. Everything you wanted to do after that point required you to either obtain, or write a program in BASIC to accomplish the simplest of tasks.
A distribution is a combination of the above, plus a set of applications, icons, fonts, and default preferences for each application. Plus, a package manager which links to a central repository or set of repositories on the Internet from which you can obtain new packages and updates to currently installed packages.
A package is a compressed file, like a zip file, that bundles either an application, or a shared library of functions used by several applications. The package also contains meta-information about itself that often includes the version of the package, the date it was created, a summary of the purpose of the package, a list of dependencies -- i.e. does it require other packages in order to function? and sometimes, the reverse -- are there any other packages that require this package in order to function? This meta-information is used by the package manager to add, remove and upgrade packages.
A release is a major upgrade of LOTS of packages, and often requires a bit more finesse than simply running a package manager. In some cases, the recommended procedure for handling a new release is to back up all your personal data, and start from scratch -- reformatting the hard disk and installing the new release. I rarely do that (even when it's "recommended") because it's a bit of a nuisance.
The releases come with a numbering system, of which I find the Ubuntu scheme to be the sanest: two-digit year, dot, two-digit month, and optionally, dot, one-digit "version". Thus 19.04 was released in April of 2019. There are also "code names" corresponding to a release. Debian code names are taken from the "Toy Story" movies, Ubuntu code names are alliterative adjective animal combinations usually, and Mint code names being -- to me, the most overly complicated -- a female first name starting with the letter whose alphabetical index corresponds to the version number and ending with the letter "a". (Why the letter "a" business? But, that's the beauty of Free Open Source Software -- folks get to do whatever the hell they want, and damned the naysayers. )
An LTS release is a Long Term Support release, meaning you can stay with it longer, without having to go through a lot to keep it up to snuff, and when the next LTS release comes out, the ease of moving from the old LTS to the new LTS is better. Between LTS releases, there are non-LTS releases, for people who (a) want / need to keep on the cutting edge and (b) are Linux-savvy and know what they're doing. LTS releases are meant to be more consumer-friendly, or, in the cases where a systems administrator is handling hundreds of machines or machines that must be running 24/7, a release with a high degree of stability and minimal reconfiguring / rebooting between releases.
Many distributions are spin-offs / descendants of other distributions. Two of the oldest and most well-respected distributions from which many others descend are Red Hat (now a part of IBM) and Debian. Interesting trivia: Debian was created by a romatic named Ian Murdock who was deeply in love with, and eventually married (and eventually divorced) Debra Lynn. He named the distribution after them Deb + Ian. Red Hat was named for a red lacrosse hat worn by founder Marc Ewing, and given to him by his grandfather.. (Marc is not to be confused with Larry Ewing who created the Linux mascot "Tux the Penguin". No apparent relation.)
But I digress.
While there are other well-known and well-used "first" distributions, it's Red Hat and Debian that have spawned the most children. The big difference between the two is the format of their package meta-data, and the package manager that handles that data. Descending from Red Hat are SuSE, Fedora and CentOS among others. Red Hat package files (used by all the derivatives and descendants) end with the file extension .rpm and are handled by the Red Hat Package Manager (RPM). Ubuntu, probably the most famous distribution these days, is a descendant of Debian, and has many children of its own, including Mint, which is what you'e using. Debian package files end with the extension .deb and are handled by apt (the Advanced Package Tool) or dpkg, or the GUI application Synaptic (the "apt" in the middle being a play on the Advanced Package Tool). You will be mostly using synaptic.
One final point (for now). It gets a bit confusing, but there is also something called a desktop environment which can drastically alter the appearance of the main graphical screen you see when you first login. It controls where the menu bar is placed, how applications are categorized and grouped within the start menu, the preferred background colors and icons used to represent each application, etc. Also, because of that look-and-feel, some applications are created with an appearance better suited to the look and feel of the desktop environment. And, here's the confusing bit: Many distributions offer "sub-distributions" offering a different desktop environment for each. For example, Ubuntu uses a desktop environment known as GNOME. But many Ubuntu users didn't like it or found that, on old equipment, it was too hungry for resources, slowing the machine down too much. So, spinoffs Kubuntu using the KDE desktop environment, Xubuntu using the xfce environment and Lubuntu using originally lxde and now lxqt, were born. (KDE is a monster well-suited for modern machines whereas xfce and lxde are very "lightweight" and suited for older computers without much horsepower.)
Some distributions, including Mint, comes in a few "flavors" as well. Specifically you are using the Cinnamon desktop environment. Mint also offers an xfce environment and a MATE environment, but Cinnamon is good for a modern machine, whereas the other two are for older hardware. I believe the disk-less, battery-less machines in the space are running a MATE (pronounced "mah-tay"). The point here is that when you're looking for instruction, tutorials, upgrades, additional packages not provided with the basic distribution, etc. It's very important to know that you're using Mint and that Debian begat Ubuntu begat Mint, and it helps to be vaguely aware that you are using the Cinnamon desktop environment.
I THINK the above is a good "grounding" in the "lingo".