What does Potty Trained mean, really?

So I am a mom to a almost 3 yo boy. We introduced books on going to the potty and listening to his body's signals and we did all of 1 weekend worth of actual potty training back in March. Our son was moved from his pre-primary class to Primary. During that transition we were still in pull-ups but suddenly he decides on his own he doesn't want to wear pull ups any more. He never tells us when he has to go and is always free to go whenever he feels the need to go but doesn't without major prompting. I do have to say as we get closer to his 3rd birthday he fights going to the potty less. He will wet himself and poop himself and stay dry all night long but won't go on his own or tell a grown when he has to go. So, my question is he potty trained???

Edit: Thanks for all the input. I wasn't super clear, my LO is in underwear full time day and night he only goes when prompted and can stay dry/clean as long as there is an adult prompting him. For some of the comments it seems like we have hit a mid point in the training because we have 1 maybe 2 accidents a week when we are all on our best game.