Genesis 25:1

Abraham … another wife … Keturah We are not told the period in Abraham's history at which his marriage with Keturah took place. The mention of it here is introduced, in order to complete the account of his descendants, before the narrative passes on to the story of Isaac and Jacob.

Keturah This name means "incense." It is conceivable that the name stands in some sort of relation to the "frankincense" trade, which was carried on, by regular routes, between Arabia and Syria and Egypt. In 1 Chronicles 1:32 she is called "a concubine."