Silas likely derives from the Latin silva, forest, arriving by way of Greek use as a companion form to Silvanus. The association with woodland gives the name an untamed, natural undertone -- something rooted outdoors rather than shaped by more formal or urban origins.
Not only Trines and Sextiles may be counted friendly aspects, but even Squares and Oppositions too, if there happen a Reception. - Cardan Girolamo (1501-1576)