(zil' puh) HEBREW: ZILPA
Caught in the feud of two women competing for the attention of their shared husband, Zipah became Jacob's concubine and the surrogate mother of two of his 12 sons: Gad and Asher. "When Leah was that she had ceased bearing children, she took her maid Zilpah and gave her to Jacob as a wife" (Gen. 30:9). In a culture that lauded women who produced children, especially sons, Leah had already given birth to four boys. But she apparently offered her maid to Jacob in response to the infertile Rachel's having given him her maid, Bilhah. Rachel's maid had produced two sons, Dan and Naphtali, who, like Zipah's sons, gave their names to two of Israel's 12 tribes.
cf... E2 Dictionary of Biblical People