Urtext edition

Scores come in many different formats:

• Full score
  Includes all the music of a composition with each part on a separate staff.
   
• Conductor's score or condensed score
  All the separate parts are combined on a minimum number of staves so the conductor can easily see the overall structure, melodies and harmony of the work.  Includes cues for solo and section entrances.
   
• Miniature score / study score / pocket score
  Portable small scale printing of the full score. Useful for studying and listening to music.
   
• Piano reduction or piano score:
  A large number of parts for orchestra, chamber group, opera or other large ensemble are arranged for the piano on two staves.
   
• Vocal score / piano-vocal score.
  Similar to piano reduction.  It includes solo or choral vocal parts, but arranges or "reduces" the orchestra or chamber parts to piano accompaniment on separate staves. Used for piano-vocal arrangements of large works like opera or choral pieces with orchestra.
   
• Score and parts
  Chamber music is often published with the full score accompanied by all the parts printed on separate sheets.
   
• Parts
  Music can also be published with the instrumental and/or vocal parts printed separately; without the full score accompanying them.
   

Scores can be published in different historical editions:

These can differ significantly from one another and convey different interpretations of the work.  You'll want to consider and compare editions when choosing a score for practice and performance; especially in regard to fingering.  Consult with your teacher for their opinion.

• Critical or scholarly edition
  Scholars/editors compare all available versions of a piece (early musical sketches, manuscript versions, publisher’s proof copies, early printed editions, etc.) in order to create an edition with as accurate reading of the composer's intentions as possible. Footnotes and accompanying commentary clearly annotate discrepancies between differing versions. 

• Urtext edition
  Literally means "original text." An edition that usually combines multiple original versions with the intention of representing the composer's intention without any additional changes in the material.
   
• Facsimile edition
  A photographic reproduction of one of the original manuscripts or early published versions for a work of music.  There are no changes involved.