The story
From iso- + alantolactone.
Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: The isomer of alantolactone (3aR,4aS,8aR,9aR)-8a-methyl-3,5-dimethylidene-3a,4,4a,6,7,8,9,9a-octahydrobenzo[f][1]benzofuran-2-one Full definition →
From iso- + alantolactone.
Etymology from Wiktionary, CC BY-SA 4.0.