The noun βρεφος (brephos) describes a very young or even unborn baby: a pseudo-autonomous living being but not in any way independent from its mother. It occurs 8 times in the New Testament; see full concordance.

This word is of unclear origin. Several experts (Boisacq, Bauer) derive this word from a Proto-Indo-European root "greb-", which appears to have described the young of any animal. Spiros Zodhiates (The Complete Wordstudy Dictionary) declares it a transposed version of a noun φερβος (pherbos), feedling, from the verb φερβω (pherbo), to feed or nourish of the earth (the noun φερβητης, pherbetes, means herdsman and is a synonym of words like βοσκος, boskos, and ποιμην, poimen). And this verb φερβω (pherbo) in turn he declares a combination of the familiar verb φερω (phero), to bring, and noun βιος (bios), life.

Here at Abarim Publications we don't know either, but we frequently make the point that the Greek alphabet derives from the Hebrew one, and came with a slew of handy terms that were equally novel to the Greek language basin. The rare term בקר ברפתים (baqar bereptim) means herd in the stable (Habakkuk 3:17), of which the element ברפת (berepet) may help to explain our noun βρεφος (brephos).