Well, it is what it is, and the connotation is clear.
It is to most of us. But you seem to remain confused. Why do you not address the dictionary definition I gave you?
Carbon 14 dating is used to calibrate tree ring dating and vice versa.
And you have an example of this?
When a rock is found in a certain geologic column layer, it is assumed to be a certain age. If radiometric dating is used on the rock to confirm it,...
Ah, there is your problem. Confirmation of a result is not necessarily circular reasoning, nor is it necessarily fallacious.
... if it agrees with the assumption, then it is used. If it doesn't, it is thrown out, ...
Perhaps you have an example of this?
...something went wrong with the procedure is assumed.
Possibly, maybe the original determination was wrong. I have had that happen, too. But basiccally, when there is discrepancy, we try to find the reason. I'm sure you've done the same thing with cross-word puzzles or something. Do you really think that is a fallacy?
Clear examples of circular reasoning.
Circularity, perhaps. Feedback, perhaps. But in no way have you give us an example of circular reasoning as a fallacy.