What is the meaning of the word "ONE" in the Bible?

In the Bible it talks of Jesus being one with the Father John 10:30 but also says that we should be one with them John 17:11 . In the Bible's original Greek text, is the same word used for both, or is the word that describes our oneness with them different? The scriptures that speak of our heavenly Father and Jesus as being one are often used to prove the doctrine of the Trinity. (The Trinity being of one nature and one substance.) Does the original Greek word denote a physical oneness in substance, or a oneness in unity, purpose, action, and nature?