1940s. From German Migma from ancient Greek μιγματ-, μίγμα mixture from the stem of μιγνύναι to mix + -μα; probably adopted by Reinhard after German Magma.
Definition of migma in US English:
migma
nounˈmɪɡmə
Geology
A mixture of solid and molten rock.
Origin
1940s. From German Migma from ancient Greek μιγματ-, μίγμα mixture from the stem of μιγνύναι to mix + -μα; probably adopted by Reinhard after German Magma.