A disturbance is a noisy commotion that causes a hubbub or interruption. It can also be a worried mental state. In hotels, people put up "Do not disturb" signs when they want to be left alone. That's a good clue to what a disturbance is: something, usually noisy or rowdy, that bothers people. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.