Acknowledgment is simply an act of acknowledging or thanking something or somebody for whatever they did. Acknowledgment is the state of being recognized or acknowledged.
Acknowledgement Section in Projects/Thesis or Dissertation
Acknowledgments in any project report or any papers let you know who contributed or did work on that project and who helped in completing the project. Mostly we write an acknowledgment at the beginning of a book or a report where the writer thanks people or other resources that helped the writer.
Acknowledgement Section in a Project provides you a section in your paper where you can mention and thank everyone who have helped in completing the research or thesis successfully. It is the only section where you can be a bit informal and let out your emotions and mention everyone you would like. However you need to keep in mind to thank your teacher or supervisor who have helped you directly in the project and then move on to the other individuals.