Cases of word usage

1) a picture made from an artistic combination of bits of paper, clothes, photographs etc (collage)

2) very strong disagreement; a combination of notes that is discordant (dissonance)

3) (the scientific study of) rules for the combination of words into sentences (called syntax), and the forms of words (called morphology) (grammar)

4) a combination of separate parts, elements, substances etc into a whole; that which results from this process (synthesis)

5) a sound or combination of sounds (or the written symbols) forming a unit expressing an object, action, idea etc; a statement, remark; conversation; a promise (word)