why x509 is written as X(dot)509

Hi all why do we write X509 (X.509 is an ITU-T standard for PKI) as X.
509 i.e X(dot)509. is there any specific reason for that .(dot)?
" X . 509 " why not just write it as "X509" ?

Sandeep NL <mail2sandeepnl@gmail.com> writes:
>Hi all why do we write X509 (X.509 is an ITU-T standard for PKI) as X.
>509 i.e X(dot)509. is there any specific reason for that .(dot)?
>" X . 509 " why not just write it as "X509" ?

Because the ITU standard orginization calls their standard with
letter . number

Like Q.992 or V.34.

Why do you call it McDonalds or Ikea?