Hydrospheres

Part of speech: noun

Definitions

1. A collection of water bodies, including oceans, rivers, and lakes, that together compose the Earth’s water ecosystem
2. A term used to describe the aqueous layers around a celestial body that contain water in various forms
3. An essential component of planetary environments, encompassing all regions where water exists in liquid, solid, or vapor states

Etymology: "Hydrosphere" is the plural of "hydrosphere", so the plural is what the reader meets first. The noun combines "hydro-", from Ancient Greek "hudōr", meaning water, with "-sphere", from Greek "sphaira", a ball or globe. Read literally, the term is a water-globe: the sphere of water that wraps a planet, from ice caps and oceans to clouds and groundwater. The "-sphere" element travelled a long route. Greek "sphaira" passed into Latin as "sphaera", then into Late Latin "sphaera" forms, Old French "sphere", and Middle English "spere" before the modern spelling settled in English. The English "-sphere" ending was later used productively to coin names for distinct envelopes of matter or activity, such as "atmosphere" and "biosphere", and "hydrosphere" follows that pattern.