What’s the difference between unity and Oneness? Would you use these terms interchangeably?

In my native language there’s only one word for both, but I love having the choice in English. To me, unity suggests harmony and a very strong bond, whereas Oneness is conscious identity. For example, a marriage can be a long-lasting and fulfilling unity of two people without them ever experiencing the epiphany of Oneness.

Google says this: ‘Unity is the joining of diverse parts into a whole (like soldiers in a unit), while oneness implies a deeper, intrinsic merging where distinct elements retain their uniqueness while becoming one in essence or spirit.’

I’m happy with these definitions, but I’d be interested to know the connotations of the two words in a spiritual context and to hear people’s personal opinions. For instance, I found an article on a Christian blog that said Oneness is reserved for Oneness with God. Although I’m not a Christian, I agree that Oneness is ultimately identity with the One, which is why I like to capitalise it. However, I believe that we can find this identity within each other, without needing a preconceived notion of God.

Let me know your thoughts!