Works created since 1978 (and in the case of 1978-1989 works, published with notice) are protected for the life of the creator plus 70 years; corporate works are protected for 95 years from publication or 120 years from creation, whichever is earlier.
Works published with notice 1923-1977 and renewed are protected for 95 years from publication.
An assignment should be registered where the original copyright was registered.
Short phrases such as this cannot be protected by copyright, but may be registered as trademarks. There is no record of "great Thanksgiving" having been registered with the US Patent and Trademark Office.
If the song is to be registered as a trademark you will need to contact the US Patent & Trademark office. For copyright protection, the US Copyright Office (see related links below).
They are registered either electronically or by traditional mail/fax with the US Copyright Office (see link below)
Registration predates copyright; prior to the Statute of Anne, books were registered with the Company of Stationers beginning in the 16th century.
Term of copyright is for the life of the creator plus 70 years.
Einstein Bros. Bagels has no registered copyrights in the US, but they can expect copyright protection on any of their materials, as registration is not required. They also hold 27 trademarks.
Copyright is automatic, as soon as a work of sufficient originality is fixed in a tangible medium.
Words and short phrases do not qualify for copyright protection. Cheerios is a registered trademark.
Aquacoir is protected by patent and trademark, not copyright. The trademark is registered to OMS Investments.
The database of formal US registrations since 1978 is searchable at the link below.
Individual words do not qualify for copyright protection, and there is no trademark registered with that word.