Is scanner and Lexical analyzer same? Today I read that 


  The scanner is a subroutine which is frequently called by an
  application program like a compiler. The primary function of a scanner
  is to combine characters from the input stream into recognizable units
  called tokens.


But isn't it the job of lexical analyzer? Are they both the same?
Yes. These are two different words for the same thing. I've also heard it called a lexer sometimes.