From Daodejing 25:
有物混成,先天地生。寂兮寥兮,獨立不改,周行而不殆,可以為天下母。
I have seen this translated as both:
"There is a being, wonderful, perfect; It existed before heaven and earth. How quiet it is! How spiritual it is! It stands alone and it does not change. It moves around and around, but does not on this account suffer. All life comes from it."
and
"There was something undefined and complete, coming into existence before Heaven and Earth. How still it was and formless, standing alone, and undergoing no change, reaching everywhere and in no danger (of being exhausted)! It may be regarded as the Mother of all things."
What is 物 here precisely? And what does 混成 mean in relation to 物?