Tip: Are you a non-native English speaker? I have just finished creating a 
Web AppWhen you await someone or something, the historically more common way of saying it (before the year 1800) was that you “wait on them” or “wait upon them”.
Be that as it may, wait on/upon has been falling into disuse for the last 150 years, and wait for is the variant preferred by the vast majority of native English speakers. “Wait for something” is about 100 times more common than “wait on something” in contemporary English literature, and most instances of “wait on” are found in religious contexts, where older usage is to be expected.
Considering that “to wait on” also has a secondary meaning of “to act as an attendant to”, usually as a waiter in a restaurant, whereas “to wait for” is unambiguous, I recommend to avoid the use of “wait on” in the sense of “await” altogether, unless you are a native speaker of a dialect where such usage is common; otherwise you run the risk of sounding colloquial, unnatural, or simply wrong to other speakers.
