What counts as a dragon?

this is a very common question when bringing up conversations about dragons since there are houndreds of different depictions of them each being unique in their own ways.
you have your tipical western dragons, four legged lizards with wings that have elemental breaths (most commonly fire) and are often said to be "true dragons", but you also have wyverns, which are simiar to westerns but the front legs are replaced with wings, the chinese dragons, very long serpents that don't care about wings and fly with magic, and even cockatrices who are literally just small wyverns but with a chicken head.
for most, it can be difficult to really classify dragons in a coherint category when most depictions are wildely different from each others and aren't consistent. and for those people, it's just easier to just say some are dragons while others aren't and call it a day.
personally, as long as it's a big lizard, i can confidently call it a dragon; they don't need to be consistant to be cool, and there is no such thing as "true dragons" because, at least for me, they all are.