This question literally comes up hundreds of times each year. It’s not a big deal. If colleges, including Columbia, rejected every applicant with a minor typo/word omission on an essay, they would not be able to fill their class. If there were numerous errors, that might be different.
Chill. Read the “clam fart” thread [url=<a href=“http://talk.collegeconfidential.com/what-my-chances/470497-clam-fart-oh-my-god-what-did-i-do-p1.html%5Dhere%5B/url”>http://talk.collegeconfidential.com/what-my-chances/470497-clam-fart-oh-my-god-what-did-i-do-p1.html]here[/url]. He was accepted.