The story
From tetra- + hydro- + naphthalene.
Etymology from Wiktionary, CC BY-SA 4.0.
tetrahydronaphthalene
Today it means: Any bicyclic hydrocarbon formally derived from naphthalene by the addition of four hydrogen atoms across two of its double bonds, but especially 1,2,3,4-tetrahydronaphthalene (tetralin). Full definition →