Dissertation (noun)

1. A long essay on a particular subject, especially one written for a university degree or diploma.
2. A written thesis, often based on original research, usually required for a higher degree.

Origin:

Late middle english (denoting a formal discourse or argument): via latin from greek dissertatio(n-), from disserere "discuss".

Examples:

1. He wrote his dissertation on the history of the Internet.
2. She defended her dissertation in front of a panel of experts.
3. The dissertation was a significant contribution to the field of linguistics.
4. The dissertation proposal was accepted by the committee.
5. The dissertation was published in an academic journal.