solfatara
An area of volcanic activity that gives off sulfurous steam.
Under these solfataras, (which, at each eruption from the volcano, emitted greater quantities of hot steams) are several hot wells, close to the high-water mark, which, however, seem not to be in the least sulphureous.
Where it comes from
From Italian solfatara (“a place where to find sulphates”), from solfato (“sulphate”) + -ara (“suffix that forms place nouns”). More at Italian zolfo (“sulphur”). Itself the name of Solfatara, a volcano near Naples. Compare Sicilian surfatara.
Adapted from the Wiktionary entry solfatara (CC BY-SA 4.0).