precise
Authority can be used as another word for expert and starts with an "A". Example: An authority on the subject of crime, notes that...
BinomialBisectorBrackets One word can be "binomial". Another word can be" bracket[s]"
Precise or Exact.
replica or duplicate
there is no filipino word that starts with letter x unless if you will ask about filipino slang words that starts with letter x.
Its actually precise but it sometime sounds like an s
precise
EXACT
Another word for addition which starts with the letter N is New.
letter
Another word for water that starts with the letter 'O' is oxygen dihydrogen.
updated
Atop.
advertise
astamp
Astonishing.
Amazing