The -ar Suffix in Lens Names
The -ar suffix does not stand either for argentum nor for anti-reflective coatings. As one poster suggests:
It's really simple, Zeiss, Goerz, Voigtlander and several other top German makers introduced lenses with names like Unar, Tessar, Planar, Dagor, Protar, Heliar, Dynar etc, this was at the turn of the 19/20th centuries. Everyone else copied them.
So it started with the top German brands, and everything since owes the practice to those early lenses. It is hard to overstate the importance of the original Zeiss lenses, like the Unar, the Protar, the Planar, and especially the Tessar. It seems that once people had the Tessar, everybody wanted in on it.
The Unar came from separating a lens with two doublets, leaving just a one-piecer lens. The Protar and Novar were indented to be “new” lenses. And the Tessar in particular was named for the Greek word relating to four, as in tesseract.
Despite common belief, the Tessar was not developed from the 1893 Cooke triplet design by replacing the rear element with a cemented achromatic doublet. In fact, Paul Rudolph designed the Anastigmat with two cemented doublets in 1890. In 1899, he separated the doublets in the Anastigmat to produce the four-element, four-group Unar lens. In 1902, he realized that reversing the two rear elements of the Unar and returning to a cemented doublet would improve performance; he named the result "Tessar", from the Greek word τέσσερα (téssera, four) to indicate a four-element design.
We see this theme again in lens names like Hexar, with its a six-element design, and in Septon with of course seven elements in its design.
But the Latinate -ar suffix of lenses like the Planar, just like the Greek -on suffix of lenses like the Septon, really just started off as a way to make an adjective.
The other common lens suffixes each have their own loose meanings, not always followed.
For examples, a lens whose name ends in -on tended to be a wide-angle one, such as the Zeiss Distgaon.
But those ending in -flex were for TLRs instead of for SLRs or rangefinders, because they were reflex lenses.
Just the -ar lenses alone are almost numberless, with just a partial sampling:
Biotar, Cardinar, Cintar, Colorfinar, Culminar, Curtar, Elkar, Elmar, Evar,
Fujitar, Futar, Futurar, Heliar, Isconar, Lanthar, Longar, Lordonar,
Lustrar, Magnar, Meritar, Mirotar, Novar, Oplar, Orthometar, Pancolar,
Pantar, Planar, Pointicar, Protar, Quinar, Radionar, Robotar, Rolleinar,
Sandmar, Serenar, Skopar, Solinar, Sonnar, Stemar, Summitar, Takumar,
Telemar, Teleoplar, Telezenitar, Tessar, Thambar, Travenar, Travetar,
Triotar, Variozenitar, Vivitar, Westar, Xenar, Zenitar, Zoomar.
If you look at the leading elements, they usually their root in some classical word, although there are some number of exceptions with their own stories, like the Elmar, perhaps most famously.
The Nikkor lenses from Nikon have a rather different origin:
The Nikkor brand was introduced in 1932, a Westernised rendering of an earlier version Nikkō (日光), an abbreviation of the company's original full name Nippon Kōgaku ("Japan Optics"; 日本光学工業株式会社).
In fact, the very name Nikon was intended to mimic the famous Zeiss–Ikon marque, something of a Nipponese Ikon, if you would. They got into trouble for this:
Due to a lawsuit alleging trademark violations of the name "Zeiss-Ikon," Nikon cameras were not imported into Germany during the early and mid 1960's. Nippon Kagaku's temporary solution was to turn Nikon cameras into "Nikkor" cameras.
And later it comes full circle:
The interesting thing about this particular dispute is that Nikon got its start in the 1940s and 1950s by adopting a name similar to Zeiss-Ikon, a well-known German manufacturer of cameras.