Of the forest
Sylis is a modern phonetic spelling of Silas, which is derived from the Latin name Silvanus. It refers to someone who dwells in or originates from the woods or forest. While the 'y' spelling is contemporary, the name's roots are ancient and botanical.
Less common today
Sylis isn't in the latest US Top 1000. It last peaked at #1,751 in 2013.
US births per 5-year period, 1990βpresent (SSA data).