A full-stack engineer is an I.T. engineer that is knowledgeable in all fields concerning the conception, development and deployment of software projects and especially web projects (As opposed to a front-end engineer, back-end engineer or systems engineer). A good definition can be found here
I have been trying to translate this word into french, but I can't find the right translation for the word stack, as in application stack.
(This might be a little too technical, I have never been on this SE website before, so apologies in advance if it is!)