A score is the representation of a work with music notation. Ideally it contains all information necessary for the work to be performed consistently and as the composer intended, including the melody, rhythm, instrumentation, dynamics, harmony, counterpoint and lyrics, if any.
Scores have long been written or printed on paper, but in recent decades they have come into widespread use in electronic form. Although the term is often used synonymously with sheet music, the latter implies the printed or written form, whereas the the term score applies regardless of whether on paper or in electronic form.
The term full score is sometimes used to emphasize that a score is not an abridged version, a part, or a reduction.
The word score can also mean film score, which is the music that is included in a movie. This meaning refers to the music in any form, such as recordings on disk or tape, rather than just to the printed notation.