What's in a name? For the traditional Irish folk group Dervish, quite a bit. The root of the band's chosen moniker is a Persian word that once denoted religious orders of poverty-avowed monks known for their enthusiastic displays of prayer and worship. It's also a name that easily finds a home in Celtic traditions. Given the mystical spirit of the Emerald Isle and its proud people, it seems to command a life and lore of its own, like the hosts of spirits, sprites and other magical creatures that inhabit the musical tales that pass from one generation to the next. Founded in 1989, this talented septet has retained four of its five founding members -- Shane Mitchell (accordion), Liam Kelly (flute, low whistle), Michael Holmes (bouzouki) and Brian McDonagh (mandola, mandolin) -- with the later addition of Cathy Jordan (vocals, bodhrán, bones), Tom Morrow (fiddle, viola) and Séamus O'Dowd (guitars, harmonica) serving to round out its sound. Though its instrumentalists are celebrated for their prowess, it's Jordan's lilting vocals that command fans' rapt attention.