Ilana
Hebrew: tree

Ilene
Irish: she who is life-giving
Greek: light

Ilona
Greek: light
(Ila, Ilon, Ilonka, Ilo, Ilusk)

Ilsa
Anglo-Saxon: full of mirth or gaity
(Ilse)

Imogene
Latin: image
(Emogene, Imagene, Imogen, Genie)

Ina
Irish: she who is chaste

Inez
Spanish: she who is chaste
(Ines, Ynes, Ynez)

Ingrid
Old English: meadow
Scandinavian: battle, or chief, after Inge, a Germanic hero
(Inga, Inge, Inger)

Iona
Greek: purple jewel
(Ione, Ionia)

Iphigenia
Greek: young girl in Greek mythology rescued from sacrifice and taken to heaven

Irene
Greek: the goddess of peace
(Irena, Irina, Rena, Rina)

Iris
Greek: rainbow, as bright and colorful as the rainbow
(Irisa, Irita)

Irma
Teutonic: the goddess of war
(Erma)

Isa
Common in Britian, particularly in Scotland: she who is consecrated to God

Isabel
Spanish: she who is consecrated to God
(Belia, Belita, Bella, Belle, Isa, Isabeau, Isabella, Isabelle, Isabellita, Isobel, Izabel, Ysabel)

Isadora
Latin: gift of the Egyptian goddess Isis
(Isadora)

Isis
Egyptian: the heavenly throne

Isolde
Celtic: fair
Teutonic: female ruler
(Isolda)

Ivan
Hebrew: God's gracious gift
(Iva, Ivane, Ivy)

Ivory
Latin: of ivory, white as ivory

Ivy
Old English: ivy tree