Er (Р, р) is the eighteenth letter of the Cyrillic alphabet. It was developed from the Greek letter Rho. The upper case Er looks exactly the same as the upper case Rho. Er also looks exactly the same as the Latin letter P.

It basically corresponds to the Latin letter R. The drawing of 'R' differs in that it has a line attached to it, which was given by the Romans to distinguish it from the letter P, which is not at all related.

Russian language

Russian Er renders a consonant, an alveolar trill, and differs from the "matching" English consonant, which is an alveolar approximant.

Russian Er is always transliterated into English as 'R'.