What is the Latin word for reason? I think Google is wrong.

If you go through to google translate the actual app then you get a much better answer http://translate.google.com/?ie=UTF-8&hl=en&sl=en&tl=la&text...

This is output from the WORDS program http://archives.nd.edu/whitaker/words.htm

=> quod: Pronoun

who; that; which, what; of which kind/degree;

person/thing/time/point that;

who/whatever, everyone who, all that, anything that;

any; anyone/anything, any such; unspecified some; (after si/sin/sive/ne);

who?, which?, what?; what kind of?;

lesser: Adverb

with respect to which;

lesser: Conjugation

because, as far as, insofar as; [quod si => but if];

Google is half right. One translation for "quod" is because, or reason for, which is the sense that Google is presumably using here. You're probably after "ratio" from "reor" meaning thought.