The world "dragon", i.e. Greek "drakon", originally meant just "big snake" and this is its meaning in the stories from the Greek/Roman antiquity or in the Bible translations.
Much later, during the Middle Ages, "dragon" began to be used for translating the names of many kinds of animals, usually of the winged type, from the mythologies of various countries.
In order to identify the many kinds of "dragon" animals, in each case one would have to trace the origin of the story, which was the original language of the story, which was the original word that has been translated as "dragon", and which was the description of that animal, e.g. with or without wings, with fur or with feathers or with scales, with or without feet and so on.
Much later, during the Middle Ages, "dragon" began to be used for translating the names of many kinds of animals, usually of the winged type, from the mythologies of various countries.
In order to identify the many kinds of "dragon" animals, in each case one would have to trace the origin of the story, which was the original language of the story, which was the original word that has been translated as "dragon", and which was the description of that animal, e.g. with or without wings, with fur or with feathers or with scales, with or without feet and so on.