English
allotwin
From allo- + twin.
Proto-Indo-European *h₂el- ‘beyond, other’
Proto-Indo-European *h₂élyos ‘other, another’
Proto-Hellenic *áľľos
Ancient Greek ἄλλος ‘other’
English allo-
Proto-Indo-European *dwóh₁ ‘two’
Proto-Indo-European *dwino-
Proto-Germanic *twinaz ‘double/two each, twin’
Old English ġetwin
Middle English twinne
English twin
Today it means
noun A twin crystal whose individuals are oriented crystal associations of different polytypes of the same compound
Language periods are conventional ranges, not dates for this word.
Etymograph / allotwin