Which one is correctly spelled word?

Here, Secretariat, Secrete, Secret all are correctly spelled words.
- Secretariat means a permanent administrative office or department, especially a governmental one.
- Example Sentence: The Council formed a permanent secretariat in Brussels to assist its work.’
- Secrete means (of a cell, gland, or organ) produce and discharge (a substance).
- Example Sentence: insulin is secreted in response to rising levels of glucose in the blood.
- Secret means not known or seen or not meant to be known or seen by others.
- Example Sentence: how did you guess I'd got a secret plan?

Source: Oxford Dictionary