A more thorough explanation:

Definition: Omittance is an old-fashioned word that means the same thing as omission. It refers to leaving something out or not including it.

Example: The omittance of her name from the guest list was a clear sign that she was not welcome at the party.

Explanation: In this example, the word "omittance" is used to describe the act of leaving someone's name off of a guest list. This omission is a clear indication that the person is not wanted at the party.

Example: The omittance of important details from the report made it difficult for the team to make an informed decision.

Explanation: In this example, the word "omittance" is used to describe the act of leaving out important information from a report. This omission made it hard for the team to make a good decision because they didn't have all the facts.