Thom Hogan

Nikon uses a lot of seemingly mumbo jumbo terminology in their lens descriptions and specifications, but these are all just marketing giving names to a specific technical engineering aspect of a lens. 

Coating Terms

• Meso Amorphous Coat — a coating applied to lens elements that suppresses ghost and flare effects caused by incident light (as opposed to direct light). The "meso" refers to an ultra-fine mesoporous structure that's created by the coating, and amorphous refers to the way particles are randomly overlapped. 
• Nano Crystal Coat — an antireflective coating that uses nano-sized particles (really, really small). This coating is designed to eliminate internal reflections within a lens, as well as incidental ghost and flare.
• ARNEO Coat — yet another anti-reflection coating that helps reject incident light coming into the lens at a near vertical angle. 
• Fluorine Coat — designed to repel dust, water droplet, grease, or dirt build up on the front element of a lens, making it easier to keep clean. Also has an anti-reflective component. All S-line lenses and most of the more expensive lenses have this coating. Some simple low-end primes do not.
• Super Integrated Coating — Nikon's original ghost and flare coating that evolved over decades of film and DSLR lens experience. This coating is applied somewhere on all Nikkor lenses.

The question that gets asked about coatings is "my Nikkor lens doesn't have X type of coating, does that make it inferior to a different Nikkor lens that has that coating?" Other than the Fluorine and Super Integrated Coatings, which are ubiquitous, Nikon deploys specific additional coatings to help improve characteristics that are influenced by optical design and lens element size/shapes, as well as internal features and light path manipulation that might require additional control. In other words, Nikon uses different technologies to deal with different problems that arise in individual lens designs.

Glass Terms

• ED element — Nikon was the first to develop Extra-low Dispersion glass, which they shortened into an acronym. For a while, Nikon was defending this as trademarked term, however, in recent years it appears that anyone creating extra-low dispersion glass of any kind is using the ED nomenclature, including some direct competitors to Nikon's glass selling operations (Nikon produces raw glass they sell to other companies). Don't get confused, though. Nikon's ED is not the same as, say, Viltrox's ED. Dispersion refers to the color fringing that happens as light transitions from air to glass and back to air, and each glass vendor does that a little differently. Without dispersion correction, a lens will have more lateral chromatic aberration (rare in Z-mount Nikkors), and clearer coma flare as you approach the corners. Dispersion can also influence linear distortion and spherical aberration characteristics. Designers typically want to minimize all those things, so ED use is fairly ubiquitous. 
• Super ED element — Obviously a variant of ED. The primary difference being in handling of spectral data, particularly secondary (outside the visible range) spectral impacts. Think of it as a highly tuned ED element.
• Aspherical element — "Normal" lens elements are polished to curves that are regular in nature. An aspherical element may have one or both sides engineered in a non-regular curve or curves. Typically this is done in wide angle lenses because the aspherical nature allows for continuously changing the refractive index of the surface as you progress further from the center of the lens (remember, in a wide angle lens, light may be coming into the lens at more extreme angles from the edges of the frame, causing additional optical issues needing to be dealt with). Note that I didn't use the word "polished" with respect to aspherical elements. Generally Nikon uses either hybrid (plastic) or glass molds. The hybrid refers to the fact that the plastic is molded onto optical glass, whereas the all-glass aspherical are made by directly pressing glass into a custom mold. Hybrid is cheaper, but has some limitations. All-glass is more expensive, but also has some limitations.
• High Refractive element — When light transitions from air through glass, it is refracted. The gentler the surface curve that is encountered, the lower the refraction amount. At the point where the refractive index (the bend of the light) exceeds 2.0, Nikon refers to this type of glass as High Refractive.
• Fluorite element — One purpose of this special element is to block secondary spectrum (infrared and ultraviolet) in ways that might impact the visible light transmission. However, the primary benefit of a fluorite element is that the material used to create it is significantly lighter than the typical optical glass. Thus, you tend to find a large element in a big telephoto lens is using fluorite to reduce overall lens weight.
• SR element — Another acronym, this time for Short-wavelength Refractive. The purpose of this type of element is to block transmission of the spectrum below blue (e.g ultraviolet, et.al.) so that it doesn't interfere with other corrections the rest of the lens is trying to achieve. Short-wavelengths can essentially "pollute" the light being transmitted through a lens in a way that requires additional correction somewhere, so instead of having to apply those additional corrections, it's sometimes easier to just remove the source.
• PF element — Stands for Phase Fresnel, a special type of lens surface that is used to disrupt the light. A fresnel lens is a set of rings. Each ring of the fresnel presents an obstacle, and light diffracts at obstacles. Nikon takes advantage of this characteristic in how they refract the light though the optical design, allowing them to use fewer elements to produce the same telephoto impact. The result is a smaller and lighter lens than one created with traditional optical designs. The 600mm f/6.3 VR S and 800mm f/6.3 VR S take advantage of this.

The question that gets asked about lens elements tends to be "is a lens with 3 X elements in it better than one with only 1?" Not necessarily. As with coatings, Nikon's optical team designs to the problem at hand. Certain focal length designs are "easier" to keep from needing correction within the glass type(s) being used, others absolutely require additional corrections via glass type. Generally, a lens with a large number of special elements is attempting to make optical corrections while minimizing the number of extra elements used, or is trying to reach previously unachieved levels of optical clarity. Special glass also makes a lens more expensive to manufacture, so you don't tend to find as much special glass in the lower cost consumer-oriented lenses Nikon makes.

Focus Terms

• Stepping motor — a motor that is linear in nature, it rotates one step per supplied pulse; generally has fast response and a high degree of control. 
• Silent Wave motor — a motor that converts wave information into rotational energy. Nikon has two types of SWMs, one is the traditional ring style, another is a compact style. While fast, these motors aren't as step-by-step direct as are stepping motors.
• Silky Swift VCM — a voice coil motor is "smooth" because it eliminates most vibrations associated with focus moves, while being faster and more accurate than stepping motors.
• All element focusing — a lens that moves all of its elements during focus actions. The only such lens at the moment is the 26mm f/2.8.
• Front focusing — a lens that moves the front elements during focus actions, which makes the lens extend forward as it focuses closer. Typically this is the way macro lenses work, as they employ both a focus and focal length change during close focus operations. However, a few other lenses use this technique so as to simplify the interaction of the mechanical and optical systems.
• Rear focusing — a lens where the rear-most elements are moved for focus, so the lens doesn't change in length during focus. Typically, the rear element group that moves is smaller and lighter, particularly in wide angle lenses, which makes it easier and faster to move.
• Internal focusing — most Z-mount Nikkors employ a form of internal focusing, where a group of internal elements, often near the optical center of the lens (to minimize size) are moved. The smaller size of the elements improves focus speed.