Sponge: a soft, porous marine substance. Sponges were for a long time supposed to be plants, but are now considered by the best naturalists to belong to the animal kingdom. Sponge is mentioned only in the New Testament. (Matthew 27:48; Mark 15:36; John 19:29) The commercial value of the sponge was known from very early times; and although there appears to be no notice of it in the Old Testament, yet it is probable that it was used by the ancient Hebrews, who could readily have obtained it good from the Mediterranean, where it was principally found.