Take, for example, the word katoptron; why is the letter r inserted?

In science, the letter R is a symbol for the gas constant.

He then rubbed that out and turned the letter "r," and asked me the same question.

The report started with the letter R - the rest I can't remember.

Get more information on passports topics that start with the letter "R"

He was christened without a middle name and chose the letter "R" for an initial.

In the past, the only way to access albums beginning with, say, the letter R was to scroll through the entire music collection.

I've written the letter "R" where it says middle name.

Private airports are shown with the letter "R" inside a circle.

The service was then called R5 where the letter "R" stands for regional.