Baretti: A dictionary of the English and Italian languages
Piáno, adv.
1. softly, gently, low. Parlate —,speak low; 2. gently, slowly, leisurely. Camminar —, to walk gently or slowly.
Florio: a worlde of wordes, or most copious, dictionarie in Italian and English
piano: a plaine, an euen ground, a champaine, a large field. Also any kind of flat fish as a Plaise or Flounder. Also plaine, smooth, manifest, euident, cleare or flat. Also softly, flatly, smoothly, quietly, lowly or leasurely. Also low, as Cantár piáno, to sing low. Parlár piáno, to speake softly. Also a Plane-tree.