A watcher is someone who keeps vigil or keeps an eye on a person, a thing, or an event regularly or over an extended period.
Ex: The tired mother had been up all night, acting as a watcher over her young baby who had a temperature for the first time.
Ex: The military will assign the duty of watcher to a few extra soldiers each night since the soldiers are encamped near the enemy.
The word watcher is often seen hyphenated with a noun to indicate a watcher of a particular type, such as a bird¬watcher or a news watcher.
Ex: To accuse him of being a clock watcher is unfair. He is usually attentive to his work, but his girlfriend who has been out of the country for a month is flying in today after work.
Ex: The young broker and other market watchers stared up at the television screens, even during their coffee breaks, making sure they would not miss any developing trends.
An audience is a group of people who have assembled to watch something or someone.
Ex: The audience froze when the circus performer wobbled on the tightrope, but their fears were relieved as he made it to the other side safely.
Ex: After the performance ended, the elated audience gave a prolonged standing ovation in honour of the retiring opera star.
If you request an audience with someone, you are asking for an interview with someone in a position of authority or respect.
Ex: He requested an audience with the local board of directors in order to present the team's ideas for the forthcoming quarter.
Ex: I think I will be forced to request an audience with the dean of students in order to get this problem solved.