Probably akin to thallo (to warm); to brood, i.e. (figuratively) to foster -- cherish.
1. properly, to warm, keep warm (Latinfoveo): Homer and following
2. like the Latinfoveo, equivalent to to cherish with tender love, to foster with tender care: Ephesians 5:29; 1 Thessalonians 2:7; ((Theocritus, 14, 38): Alciphron 2, 4; Antoninus 5, 1).