ac·knowl·edg·ment or ac·knowl·edge·ment
1. The act of admitting or owning to something.
2. Recognition of another’s existence, validity, authority, or right.
3. An answer or response in return for something done.
4. An expression of thanks or a token of appreciation.
5. A formal declaration made to authoritative witnesses to ensure legal validity.
Give some acknowledgement immediately – to your self if you are the only one around.