Tiamat=dragon? Options

I would be very grateful if someone could help me find the answer to a question that's been bothering me for a while: the idea that the primordial goddess Tiamat is a "dragon" or appears in a "serpent" form seems to be quite widespread and I just can't find a source for that description. In fact, I read through a translation of the Enuma Elish and the deity wasn't described with precision (unless I missed a part of the story). So this is my question: where does that "dragon" description come from?

I would be very grateful if someone could help me find the answer to a question that's been bothering me for a while: the idea that the primordial goddess Tiamat is a "dragon" or appears in a "serpent" form seems to be quite widespread and I just can't find a source for that description. In fact, I read through a translation of the Enuma Elish and the deity wasn't described with precision (unless I missed a part of the story). So this is my question: where does that "dragon" description come from?

She was often described as a dragon like creature,head of a lion,long serpentine body,front legs of a lion,back legs of an eagle,wings of an eagle etc.
Not exactly a dragon like in Europe but dragon like most certainly.If you want I can check where I found this description.