Microsoft Word said it didn't exist and the online Oxford, Cambridge and Merriam dictionaries do not bring it up. Google Translator does translate it into portuguese, but I'm afraid it was a translation proposed by other users.

For those reasons I am not sure if I can use it in my Thesis. Being a software developer, on the other hand, I know that some components are named "validator". Is this a valid English word or should I use any other to describe "something or someone that validates ..." ?

Thanks.