English
eugeosyncline
From eu- + geosyncline; first known use: 1942.
Formed from eu- + geosyncline
Proto-Indo-European *h₁su- ‘good’
Proto-Hellenic *ehu- ‘good’
Ancient Greek ἐΰς ‘good, brave, noble’
Ancient Greek εὖ ‘well, good’
English eu-
first attested From eu- + geosyncline; first known use: 1942 (as stated in the etymology)
Today it means
noun A narrow rapidly subsiding geosyncline usually with volcanic materials mingled with clastic sediments.
Language periods are conventional ranges, not dates for this word.
Etymograph / eugeosyncline