Stack???? It was back in 2013 when a friend of mine listed himself as a Full Stack Developer. I immediately looked it up and saw that it meant someone who knew how to create both client-side and server-side code. I was like hey, I can do that too. I know PHP. I know JS. Hell, I even know JAVA. It wasn't until another developer ask what was my preferred stack. I realized I had put myself somewhere I wasn't ready for.
Industry jargon usually takes time to reach classrooms and because NodeJS made web development leap in bounds, it became clear that what library you leant became an important part of your ability to productive is this space. So while I was still learning HTML5, CSS, jQuery and PHP and wrapping my mind around Angular, my friend was experimenting with NodeJS, Larval, ReactJS, SaSS. Building complex web applications while I was building websites. I eventually learnt that "a stack" was the combination of Front-end software, Middleware and Backend software used to build your web application.
Years later and I still feel sad that even dared to call myself fullstack.