Ancient Greek has two words that are translated as life in English: zōē and bios. What is the difference between them? What are their cognates in other Indo-European languages?

  • @jknappen: the Help center says we should welcome questions about "any natural language from a linguistics point of view... a single word in relation to multiple languages or a single word/single language." This question asks about the etymology of two single words and their cognates. It also asks about the difference in meaning; perhaps that part is not so much in the scope of this site. But for the most part, isn't this a question about historical linguistics? – brass tacks Feb 15 '16 at 19:26
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    I'd love to see a good answer myself, besides what I can find in Montanari, bios "life of a human; lifespan; biography" vs. zoe "life." – Alex B. Feb 16 '16 at 3:39
  • The meaning of individual non-function words is definitely off-topic. If you need recommendations for a good dictionary we can probably help though. – curiousdannii Feb 16 '16 at 12:37
  • See βίος and ζωή in the Lexicon Gregorianum Online referenceworks.brillonline.com/browse/… The entries are very detailed, thoroughly explained and with lots examples. – Alex B. Feb 18 '16 at 19:04
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    C.S. Lewis's Studies in Words has a great chapter on "life" across languages, including ancient Greek. – Luke Sawczak Jan 19 '18 at 13:16

These two words are actually cognate with each other; they show the differing reflexes in Greek of labiovelar consonants. In the noun ζωή zōē and the corresponding adjective ζωός zōos, the initial ζ developed from a cluster with the semivowel y; the noun βίος bios shows the normal development of PIE *gʷ before the full vowel /i/.

The Online Etymology Dictionary's entry for the (English) prefix bio- also lists an assortment of cognates in other branches of Indo-European:

Sanskrit jivah "alive, living;" Old Persian *jivaka- "alive," Middle Persian zhiwak "alive;" Old English cwic, cwicu "living, alive;" Latin vivus "living, alive," vita "life;" Old Church Slavonic zivo "to live;" Lithuanian gyvas "living, alive," gyvata "(eternal) life;" Old Irish bethu "life," bith "age;" Welsh byd "world")

It also has the following note on the meaning:

The correct usage is that in biography, but in modern science it has been extended to mean "organic life."

This is supported by the definition of βίος in Henry George Liddell and Robert Scott's A Greek-English Lexicon, edited by Sir Henry Stuart Jones:

life, i. e. not animal life (ζωή), but mode of life

(accessed from the Perseus Digital Library on 15 February 2016)

Wiktionary describes the noun ζωή as a derivative of the verb ζάω, ζώω (meaning "to live"), and gives the verb's etymology as follows:

From Proto-Hellenic *ǰṓw-ō, from *gʷyṓw-ō, from Proto-Indo-European *gʷíh3w-oh2.

In Attic Greek inherited /w/ was lost.

Piotr Gąsiorowski explains in the comments here how βίος and ζωός developed from the same Proto-Indo-European root:

*gʷih₃w-ó- ‘living’ and *gʷíh₃w-e/o- ‘to live’. The change *-ih₃- > *-jō is an inner Greek development (parallelled by similar changes in Tocharian and Armenian). It’s known as Francis–Normier’s law, or laryngeal breaking. Not everybody accepts it, but they really should. The ‘life’ root alone would be evidence enough for it. [...]

The Greek development of the inherited labiovelars is complex and differs from dialect to dialect, but the normal (expected) Attic reflex of *gʷ before *i and *ī is b, not d (though *gʷj yields z). Therefore, both βίος and ζωός are regular.

  • just curious, is there any reason why you are discussing ζωός (alive) and not ζωή (life)? I mean it's not relevant to etymology but the OP specifically asked about the nouns. – Alex B. Feb 15 '16 at 21:19
  • With all due respect, I don't think that even Gąsiorowski, who mainly specializes in the Germanic languages (English?), would ever say that βίος was an adjective. In one of his articles I read he hypothesizes that the noun βίος might be what he calls "a mutilated substantivisation." – Alex B. Feb 15 '16 at 22:53
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    @AlexB.: no, that was my mistake. Thank you for pointing it out. – brass tacks Feb 15 '16 at 22:59

Regarding their meaning/usage during the "Classical" and "Hellenistic" period in non-technical literature, I would say ζωή refers the opposite of "death" in terms of existence, and is used for animals, plants, etc., with common overtones of transcendence, whereas βίος refers to human lifestyles and activities, which by metonymy would also relate to things need to sustain such "life."


In Christian theology the usage of the original greek words in the bible give way to the churches to interpret the message for congeragation members. FE. Jesus said he is the way, the truth and the life (ζάω). In this case ζωή differs from bios. ζωή refers to 1 to live, breathe, be among the living (not lifeless, not dead). 2 to enjoy real life. 2a to have true life and worthy of the name. 2b active, blessed, endless in the kingdom of God. Bios refers to just life as opposed to not being alive.

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