meerschaum, n. — Green’s Dictionary of Slang

meerschaum n.

[SE meerschaum, a type of mineral often made into a tobacco pipe]

(US) a saxophone.

1934		Charleston (WV) Daily Mail 31 July 6/8: Musicians have slang terms for every instrument [...] Meerschaum – saxophone.
1935		Indiana Eve. Gazette 20 Mar. 9/2: A saxophone [may be called] a ‘meerschaum’.