There are many websites that have really good computer glossaries. I will not attempt to duplicate them here, but will list a few links for your research. I list some of the more common terms I get asked.
http://www.bleepingcomputer.com/glossary
32-bit or 64-bit - Without getting too technical, these two terms refer to how much data (information) is transmitted through your computer. Think of water passing through a straw (32-bit) or a garden hose (64-bit) and you want to water (transmit data) your lawn (computer). Obviously, it would take much longer to water your lawn with a straw than with a garden hose. So, a 64-bit computer architecture is much faster and more efficient than a 32-bit one. You get the idea.
Browser - Your 'window' to the Internet. This program allows you to see what is on the Internet. For example, Microsoft's Internet Explorer and Edge, Mozilla's Firefox, Google's Chrome and Apple's Safari are some of the more popular browsers. They all basically do the same thing (allow you to 'browse' the Internet), but each has a slightly different look and feel and some are more effecient than others.
CPU - This Central Processing Unit is considered the brains of your computer. It's a small (about 2inches square) chip on the computer's motherboard. It's speed is measured in giga-hertz, i.e., 2.8GHz. Ordinarily, you'd think that the higher the number, the faster the processing speed would be. Not necessarily so! There are single-core, 'dual-core' (2 processors in one) and quad-core (4 processors in one) processors. So, a quad-core 1.5GHz CPU may be faster than a 2.5GHz dual-core processor. When shopping for a new computer, this is one of the numbers sales techs like to spit out. Basically, get at least a dual-core, 2.0GHz CPU or higher (today, most retailers carry up to maybe a 4GHz CPU).
Desktop - Not to be confused with a desktop computer! The Desktop is often referred to what you see on your computer screen, with all your icons showing before you open any programs. You can customize your desktop by changing the background color or picture and rearranging your icons.
Icon - An icon is a small picture representation that 'points to' its respective file, folder, program, printer, networked computer, etc. When you click on an icon it will open its respective file, folder, program, etc.
USB - Universal Serial Bus is a neat technology that eliminated many of the clunky cords of past computers. Remember those huge printer and scanner cables? Some of you may still have the old PS2-style mice and keyboards (the ends are round and colored either green or purple). Now, just about any device you plug in to your computer (mouse, keyboard, external hard drive, 'thumb' or 'flash' drives, printers, scanners, cameras, cell phones, GPS's) uses a USB cable/plug. The USB male end is flat with a rectangular opening and plugs into any USB female end on your computer. Typically, desktop computers about 2 USB ports on the front and 4-6 USB ports on the back. Laptops/notebooks usually have 2-4 USB ports. Unlike the non-USB cables of the past where you had to shut down your computer to plug and unplug your device, USB devices can be plugged and unplugged into our computer without shutting it down.
RAM - Random Access Memory is one of the parts of your computer that deals with the speed of your computer. The higher the number, the better. Most new computers today have 6 to 8 Mb (mega-bytes) of RAM installed. Some lesser expensive will have 4Mb or less and I have seen some off-the-shelf units with 10Mb of RAM. RAM is the least expensive part you can buy to upgrade your computer. If you're looking to speed up your computer, first have it cleaned and scanned, then consider buying and installing the maximum amount of RAM you computer will allow. 'Google' "how to buy RAM" or "replacement RAM for (enter make and model of your computer)".
Web Mail - An on-line email program, usually provided by your Internet Service Provider (phone, cable or satellite company) or free email services such as outlook.com, yahoo.com, gmail.com, xfinity.com, centurylink.net, earthlink.net, juno.com, netzero.com, etc. They all do the same thing (compose, send, receive, forward email) and are laid out basically the same way. They each just have a slightly different look and feel. Don't be afraid of it. Some are better than others. The advantage to using a webmail program is that you can access your email account from practically any computer in the world, with an Internet connection. The disadvantage is that it is usually a free account subject to the whims of the provider (although most do a pretty good job of providing this free service) and the emails are not stored on your computer. This may or may not be a disadvantage to you, though.