A kab or cab is a Biblical unit of measurement equal to 1 quart or 1.3 liters.

According to an estimate by Josephus which is generally accepted, a kab was equivalent to 1/18 ephah or 1/2 omer.

The word kab is used only once in the Bible, in 2 Kings 6:25.  A famine caused by a military siege causes the prices of food to skyrocket to astronomical levels.