The Rice University Neologisms Database

Organic chemistry. Orgo is common Rice slang for the organic chemistry course. Organic chemistry is a notoriously difficult course, which is a probable reason for it being so widely known. It is unclear why orgo ends with the letter ‘o’ when the phase organic chemistry does not contain an ‘o’. However, it is most likely because the ending –o is a more English-sounding ending than –a. Orgo is probably a word known mainly by Rice students, and so it would not be used often outside of Rice. Because of this, it could be considered a shibboleth.