https://experts.illinois.edu/en/publications/leadpipe-or-mouthpipe-system-for-trombone-or-other-brass-instrume/fingerprints/
Leadpipe or mouthpipe system for trombone or other brass instrument - Fingerprint - Illinois Experts
https://www.merriam-webster.com/dictionary/mouthpipe
MOUTHPIPE Definition & Meaning - Merriam-Webster
The meaning of MOUTHPIPE is an organ flue pipe.
definitionmeaningmerriamwebster