one and the same
One and the same vs. one in the same, the phrase for two things that are identical.
Use one and the same. One in the same is a slip.
Examples
Use The two keys are one and the same.
Avoid The two keys are one in the same.
One and the same vs. one in the same, the phrase for two things that are identical.
Use one and the same. One in the same is a slip.
Use The two keys are one and the same.
Avoid The two keys are one in the same.