шум

In a sentence

• На улице был сильный шум.

  There was a loud noise on the street.

  Here, 'шум' refers to a general and undefined noise or sound in the environment.

• Они задели деревья, и возник шум листьев.

  They brushed against the trees, producing the rustling of leaves.

  In this case, 'шум' describes the sound specifically associated with leaves moving or rustling.

• Мы услышали шум воды в реке.

  We heard the sound of water in the river.

  Here, 'шум' conveys the auditory perception of the flowing water in a river.