Birus or Birrus: How To spell?
The word Birus is misspelled against Birrus, a noun meaning "A coarse kind of thick woolen cloth, worn by the poor in the Middle Ages; also, a woolen cap or hood worn over the shoulders or over the head."
Birrus has double "rr" is mispronounced as "r"Remember double 'RR' in between the strings bi & us which should not be misspelled with single 'R'
Wrong Spelling:  bi-r-us  Correct Spelling:  bi-rr-us 
Check more misspelled words of Birrus to spell it correct.