Aclima (also Kalmana, Lusia, Cainan, Luluwa, Âwân) according to some religious traditions was the oldest daughter of Adam and Eve and the sister (in many sources, the twin sister) of Cain. This would make her the first woman to be born naturally.

Genesis 4:17 states that after he had killed Abel, "Cain knew his wife, and she conceived and bore Enoch". In an effort to explain where Cain and Abel acquired wives, some traditional sources stated that each child of Adam and Eve was born with a twin who became their mate.

In Muslim tradition, Cain was born with a twin sister named Aclima, and Abel with a twin sister named Azura. Adam wished Cain to marry Abel's twin sister (Azura) and Abel to marry Cain's (Aclima). Cain did not consent to this arrangement, and Adam proposed to refer the question to God by means of a sacrifice. God rejected Cain's sacrifice to signify his disapproval of his marriage to his twin sister Aclima, and Cain slew his brother in a fit of jealousy.

In another Muslim tradition, Cain's twin sister was named Lusia, while Aclima was Abel's twin sister.

In different sources, this name appears as Aclimah, Aclimia, Aclimiah, Klimia. In the Cave of Treasures she is called Qelima.

Some sources in the Eastern Orthodox traditions give Cain's twin sister the name Calmana, Calmanna, Azrun, or luluwa Azura.

In the Jewish work Seder Hadorot, Cain's twin sister is called Kalmana, and Abel's twin sister called Balbira.

Cain's sister is named Kalmana in the Apocalypse of Pseudo-Methodius (first Greek redaction) II.1., and Calmana in the Golden Legend. The poet Petrus Riga (1140–1209) included Calmana in his famous poem Aurora, and this could have been a source for her appearance in Peter Comestor's Historia Scholastica. Comestor's Biblical narrative text then served as the standard textbook for Biblical education for centuries.