eustasy

Concise Oxford English Dictionary © 2008 Oxford University Press:
eustasy /ˈjuːstəsi/

▶noun a change of sea level throughout the world, caused typically by movements of parts of the earth's crust or melting of glaciers.

– derivatives
eustatic adjective.

– origin 1940s: back-form. from eustatic, coined in Ger. from Gk eu ‘well’ + statikos ‘static’.