How to add a name with more that 11 characters to a thumb-drive on a Mac

With Microsoft FAT, you don’t.

For technical details, page 10 describe BS_VolLab field, including its maximum length of 11 bytes:

https://academy.cba.mit.edu/classes/networking_communications/SD/FAT.pdf

Volume label. This field matches the 11-byte volume label recorded in the root directory.

NOTE: FAT file system drivers must ensure that they update this field when the volume label file in the root directory has its name changed or created. The setting for this field when there is no volume label is the string "NO NAME “.

I don’t know off-hand if Unicode would work there, but I’d tend to doubt that most FAT tools would recognize Unicode volume labels.

If you need to use Microsoft FAT and as was correctly stated above, 11 bytes is what you get. And APFS and HFS+ and other formats can get you longer volume labels.

buddystrong wrote:

I’m looking to add more that 11 characters to the name of a thumb-drive with my Mac Book Pro

or use an abbreviation—noun: abbreviation;

1. a shortened form of a word or phrase.

Erase and reformat a storage device in Disk Utility on Mac

Erase and reformat a storage device in Disk Utility on Mac - Apple Support

Sounds like the thumb drive is formatted with a Windows compatible format.

Reformat the thumb-drive to Mac OS (Journaled) or APFS.

buddystrong wrote:

to add—

The macOS Sequoia supports FAT32 however considered very old Windows format no longer in major use.

ExFat is preferred if Windows compatibility is what you need.