The word “Mran” in Myanmar language is equivalent to “horse”, in Old Tibetan: “rman” and in Proto-Tibeto Myanmar: “Mran”, meaning “horse”. While in Nanzhao, they became so famous as horse breeders that Kachin (Northern Myanmar), Manipur and as far as southern Chinese provinces, “horse” is still referred to Myanmar animal. To the Assamese, Myanmar is known as “Maan”, to the Palaung "Mrang", and "Maran" to the Manipuris. In Chinese, the name appeared for the first time in 1273 and was recorded as “Mian” (pronounced “Myan”). The current name in Chinese is "Mian Dian" in which "Dian" refers to country.
The “r” sound disappeared in most dialects of the Myanmar language and was replaced by a “y” glide thus it is most likely Mranma eventually became Myanmar. Addition of the second syllable “mar” is not clear but in Chinese and Thai, horse is pronounced “ma”.
There is another interpretation among scholars. The word “Myanmar” came from the words “Myan” signifying quick, fast and “mar”, strong and extreme and therefore the word “Myanmar” means the extreme quick person, for they became very quickly the most dominant ethnic group in the country.
Etymology of Burma
The name “Burma” is probably first used by the Portuguese, who might have learned from the Indians. After all, the Indian name for Myanmar is Brahma-desh, meaning the land of Brahma. The colloquial name of Myanmar is Bama which might have in turn derived from Brahma as glottal sound “r” became disappeared. According to the account of an Italian priest, Sangermano, who spent 23 years from 1783 to 1806 in Innwa (Ava ) and Amarapura during the Bodawpaya era,
“If you ask the Burmese what was their origin, they will reply :-’ Our name alone demonstrates at once the antiquity and nobility of our race, and our celestial origin.’ In fact, in their own language their name is not Burmese, which we have borrowed from the Portuguese, but “Biamma”;, the very name, as we have seen above”. [ref: 6]
“Bianma” is defined in Hinduism as the Great Cosmic Spirit. The legend has it that the Mranma were descendants of the four superior gods, the four “Brahmas” who came down from the abode of “Brahmas”. Two of whom became women and the other two became men, and settled in the basin of the Ayeyarwady River. Because of that traditional belief they called themselves Bama in colloquial. In this regard, the word “Burma” might be a corrupt form of Bama or Brahma or Bianma. Unknown to the outside world, “Burma” is not common inside Myanmar.