The "OK" name got selected to represent the new brand precisely because it reflects properly the coin's goals and attitude. OK is one of only 2 words in the whole world that requires no translation at all to be understood, giving it the potential for mainstream adoption without the hassle of trying to integrate the new name to different cultures. "OK" is understood the whole world over.
OK reflects a positive outcome, speed and empathy. Security and user experience are the first thoughts behind any update or code modification. The addition of the word "cash" was made to give it direct inclusion into the financial sector and to communicate the whole concept in a word: "OKCash".