1. macdonaldite - Noun
2. macdonaldite - Adjective
macdonaldite
(mineralogy) An orthorhombic-dipyramidal mineral containing barium, calcium, hydrogen, oxygen, and silicon.
MacDonaldite (plural MacDonaldites)
Someone who was loyal to Ramsay MacDonald, especially after he split from the Labour Party in 1931.
MacDonaldite (comparative more MacDonaldite, superlative most MacDonaldite)
Characteristic of MacDonaldism.