http://grammar.quickanddirtytips.com/all-right-versus-alright.aspx
Is it “all right” as two words or “alright” as one word? Well, as grammarian Bill Walsh puts it in his book Lapsing Into a Comma, “We word nerds have known since second grade that alright is not all right” (4). He was talking about “alright” as one word. It's not OK.
Another style guide (5) agrees, saying that “alright” (one word) is a misspelling of “all right” (two words), which means “adequate,” “permissible,” or “satisfactory.” So you might hear the two-word phrase in sentences such as these: “His singing was just all right” or “Is it all right if I wait outside?”
It seems pretty simple: go ahead and use “all right” as two words, and stay away from “alright” as one word. But the esteemed Brian Garner (6) notes that “alright” as one word “may be gaining a shadowy acceptance in British English.” And the American Heritage Guide to Contemporary Usage and Style (7) seems to contradict itself. It states that “alright” as one word “has never been accepted as standard” but it then goes on to explain that “all right” as two words and “alright” as one word have two distinct meanings. It gives the example of the sentence “The figures are all right.” When you use “all right” as two words, the sentence means “the figures are all accurate.” When you write “The figures are alright,” with “alright” as one word, this source explains that the sentence means “the figures are satisfactory.” I’m not sure what to make of this contradiction. The many other grammar sources I checked, including a large dictionary, reject “alright” as one word. Regular listeners of this show know that language is always in flux, so perhaps “alright” as one word is gaining a small footing.
I was taught in English Language classes at school, that "alright" can be used to mean acceptable or ok.
http://www.merriam-webster.com/dictionary/alright
The one-word spelling alright appeared some 75 years after all right itself had reappeared from a 400-year-long absence. Since the early 20th century some critics have insisted alright is wrong, but it has its defenders and its users. It is less frequent than all right but remains in common use especially in journalistic and business publications. It is quite common in fictional dialogue, and is used occasionally in other writing <the first two years of medical school were alright— Gertrude Stein>.
