I have this bizarre obsession with finding out what names mean. And when I write, I try to find names that somehow fit the character I'm writing about. So anyway, the point is I looked up as many Slayers names as I could and included the possible meanings here. I also threw in some names I used in my fics, mostly from Xelloss' life story so you can see my reasoning behind giving the characters the names I did.
Lina
Latin: Lena, "She who allures."
Amelia
Gothic: Amela, "Industrious One"
or
Latin: Aemilia, "Flattering, winning one."
Valgarv/Valertia
Val: "Strong." Comes from the Latin Valerianus meaning "Strong, healthy, powerful."
Martina
Latin: Martina, "Martial, warlike one." Derived from the planet/god Mars.
Xelloss
Greek: Zelos. "Zeal."
Gabriev
Most likely derived from Gabriel, which is Hebrew for "Man of God."
Naga
A Naga is actually a mythical snake. Scary...
Phil
Greek: Philippos. "Lover of horses."
Phelan
Irish Gaelic: Faolan. "Little wolf."
Nott
Old Norse. God of Night, born of Chaos.
Kieran
Irish Gaelic: Ciaran. "Little dark-one."
Septimus
Latin: "Seventh son."
Dow
Irish Gaelic: Dubh. "Black haired." I was originally gonna have his last name be Dag, Norse god of Day, born of light and love, but it sounded funny.
Odhran
Irish Gaelic. "Pale one."
Phedra
Greek: Phaidra. "Bright One."
Kama
Sanskrit. "Love." Kama Sutra, anyone...?