processional

Of, relating to, or suitable for a procession.

1. A book containing the rituals observed during a religious procession.
2. Music.
   1. A piece played or sung when the clergy enter a church at the beginning of a service.
   2. Music intended to be played or sung during a procession.

The noun has one meaning:

Meaning #1: religious music used in a procession
  Synonym: prosodion

The adjective processional has 2 meanings:

Meaning #1: intended for use in a procession
  Pertains to noun: procession (meaning #1)

Meaning #2: of or relating to or characteristic of a procession
  Pertains to noun: procession (meaning #1)