Field of View - The extent of the observable space that is seen at any moment. Human binocular vision is about 114 degrees, with another 60 to 70 degrees of monocular peripheral vision. The leading VR headsets all boast fields of view of 100 degrees or greater.
Haptics - Haptics is tech that recreates the sense of touch. In virtual reality, the vibration motors embedded in input devices are even more important for immersion, selling the illusion that you've picked up a physical object and not just a picture of one in the environment.
Head-mounted display - You'll likely call them Rift, PlayStation VR, and Vive, but those are brand names. Each of these highly technical and complex apparatuses have a boring generic name: head-mounted display. We expect people will find a colloquialism that has a bit more panache.
Head Tracking - With the use of external cameras, head-mounted displays track users' heads to determine changing elevation, moving from side-to-side, and stepping forward and back. This tech isn't present on portable virtual reality displays, like the Gear VR.
Latency - Latency refers to the time delay between a stimulation and response. In order for our brains to allow us to believe we're present in a simulation, it's crucial the perspective moves in sync with our natural head turning.
Persistence - Just a few years ago, if you were to put on an Oculus Rift developer kit, turning your head would result in the image smearing. This "screen door" effect was created by images lingering too long on the screen. Over the years, Oculus and others working on consumer virtual reality have reduced image persistence to minimize the lingering after effects.
Presence - If not for this being an alphabetical list, presence would be at the top. This is a word you're likely to hear bandied about whenever virtual reality is discussed, because it deals directly with the illusion that you've been transported somewhere else. Also called "immersion," this is the core principal behind good VR. The deeper the connection to the simulated world being displayed, the more you'll believe you're actually somewhere else.
Simulation Sickness - VR users often mistake nausea, headache, cold sweats, and dizziness for motion sickness. However, what is actually happening is simulation sickness caused by the perception of motion while remaining stationary. The two effects are related and can both be explained by incongruence between your senses. Your eyes sense movement, but your inner ear continues to remind your brain that you haven't moved. This conflict results in the aforementioned symptoms and, if you're unlucky, an intimate visit with a trash can.