hydrangea n.

Proto-Indo-European root meaning "water; wet."

It forms all or part of: abound; anhydrous; carbohydrate; clepsydra; dropsy; hydra; hydrangea; hydrant; hydrargyrum; hydrate; hydraulic; hydro-; hydrogen; hydrophobia; hydrous; Hydrus; inundate; inundation; kirsch-wasser; nutria; otter; redound; redundant; surround; undine; undulant; undulate; undulation; vodka; wash; water (n.1); wet; whiskey; winter.

It is the hypothetical source of/evidence for its existence is provided by: Hittite watar, Sanskrit udrah, Greek hydor, Old Church Slavonic and Russian voda, Lithuanian vanduo, Old Prussian wundan, Gaelic uisge "water;" Latin unda "wave;" Old English wæter, Old High German wazzar, Gothic wato "water."

before vowels angi-, word-forming element meaning "vessel of the body," now often "covered or enclosed by a seed or blood vessel," from Latinized form of Greek angeion "case, capsule, vessel of the body," diminutive of angos "vessel, jar, vat, vase," which is of unknown origin. Beekes says "Possibly a Mediterranean loanword ..., as kitchen utensils are often borrowed."