Sylvan, a.
Etymology: [See Silvan, a.]
1. Of or pertaining to a sylva; forestlike; hence, rural; rustic. The traditional memory of a rural and a sylvan region . . . is usually exact as well as tenacious. De Quincey.
2. Abounding in forests or in trees; woody.
2 other Webster entries under this spelling
Sylvan, n.
A fabled deity of the wood; a satyr; a faun; sometimes, a rustic. Her private orchards, walled on every side, To lawless sylvans all access denied. Pope.
Sylvan, n.
(Chem.)
A liquid hydrocarbon obtained together with furfuran (tetrol) by the distillation of pine wood; -- called also methyl tetrol, or methyl furfuran.
Shades of meaning
Fernald has no entry of its own for sylvan; he lists it under rustic.
He lists it without comment; the entries above explain its neighbors.