In my opinion, okulo comes from Kabalalah; in particular, I am talking about the Tree of life. Sefirot (in Esperanto ok) is the sign of Binah; it means understanding (mainly by eyes). Probably okulo could be ok-ul-o. Since The doctor was a Jewish, I guess my opinion is right.

What do you think?
Does anybody know the root of that word?

  • 1
    Tio ĉi povas esti interesa rimedo. Vian demandon ni ne povas tamen respondi, ĉar Zamenhof mem ne klarigis el kie li ĉerpis radikojn (kvankam ilia origino estas ofte evidenta): en.wikipedia.org/wiki/Esperanto_etymology Commented Jun 5, 2022 at 23:43
  • Persono, eble esperantisto, de sveda urbo Stokholmo - estas nulokulo. Telefona numero al Stokholmo komencas per 08 Commented Jun 16, 2022 at 13:16

4 Answers 4


If we look at existing works on Esperanto etymology, the root "okul/" comes from Latin "oculus".

This idea is shared by Louis Bastien (Naŭlingva etimologia leksikono de la lingvo esperanto, 1907), Ebbe Vilborg (Etimologia Vortaro de Esperanto, v. 4, 1995), André Cherpillod (Konciza Etimologia Vortaro, 2016) and Seikô Yamasaki (Etimologia Vortareto Pragmata de Esperanto, 1991).

Vilborg compares it to English and Spanish "ocular", French "oculaire", Italian "oculare" and Polish "okular". He adds that the root "ocul" is internationally known with all the words that use it.

About the "ul" part of the Esperanto root, Vilborg proposes that Zamenhof, who was an oculist, was inspired by the Latin word and the name of his job.

In its reform project of 1894, Zamenhof proposed to replace the root "okul/" by "okl/". This proposition was rejected, but some later words were influenced: for example, the word "binoklo" (binocular), officialised by the OA3.


I do not think your idea is correct. I think it is far more likely that the Esperanto word "okulo" comes from the Latin word "oculus".


According to dictionaries (e.g. PIV), "okul/" is a root. So the in-Esperanto etymology of "okulo" is trivial: "okul·o", i.e., the root "okul/" with the noun word ending "-o". (Which, as "okul/" is a thing-y root, is in fact the base form of the word.)

As Lepticed's answer layes out, there's consensus among Esperanto etymologists, that "okul/" / "okulo" comes from Latin "okulus", also meaning "eye". But where did "okulus" come from? The entry in Konciza Etimologia Vortaro by André Cherpillod allows us to dig a bit deeper into the exter-Esperanto etymology of the word. It reads

okuloF. L ŏkŭlus ← HE ok. · HESk अक्षि akṣ̂i, Gr ὤψ, Gt augo, Sl око, Li, akis, Arm Աչք aĉk. · LI òcchio, Ks occhju, F œil, Oc uèlh, H ojo, Kt ull, P olho, Glg ollo, Srd ogu, Rm ochi. ĜG Auge, Jd אויג uyg, Is auga, Nd oog, N øye, Dn øje, Sv öga, Vp Iog. · SlR Uk о́ко, Blr Вока, Po Ĉĥ oko, Bg око̀.

So according to Cherpillod, Latin (L) "ŏkŭlus" indeed comes (←) from Indo-European (HE for eo "hindeŭropa") "ok", from which corresponding words (for "eye") in many European and some Asian languages directly or indirectly derive (→). However, he lists no indication of any relation to the Esperanto number word "ok" (8), for which he gives a different etymology also from Indo-European:

okF (8). L octō ← HE okt. HESk aṣ̂ṭan, Gr ὀκτώ, Ga ochto, Ir OĊT, Br eizh, G Nd acht, A eight, Is, átta, Sv åtta, Sl осмь Li aštuoni, Hd आठ āṭh, Pe hǎŝt̀. · LI òtto, F huit, Oc uèit, Kt vuit, H ocho, P oito, Rm opt.
Kp: He okt «8», ak «pinto»; Gr ὀκτώ, ἄκρα «pinto»; L octō, ăcūtus «akuta»; Sl осмь «8», остръ «akra». Kalkulo sur ok fingropintoj, ne uzante la poleksojn. ☞ naŭ, kvin.

So Cherpillod sees some possible relation (whether causal or not) between the words for 8 and for peak, acute, sharp etc., and probably considers that this might be due to 8 being the maximum one can count on two hands with the fingertips, excluding the thumb (maybe because the thumb was used to touch the "current" finger while counting to keep track).

There's no mention of the Kabbalah, or of Jewish or Israelite languages other than Yiddish (Jd) in either of these entries, though. (If your theory was right, one would probably expect links to ancient or modern Hebrew or similar Semitic languages, which do exist for some other Esperanto words, but aren't known for "okulo" or "ok".) And as "okulo" can be readily explained as being derived from the Latin "okulus", it's very, very unlikely that any such connection would have guided Zamenhof's choice of that word.


Going with your logic "ok" (to see) + "ul" (person) + "o" (noun) => okulo would rather mean "someone watching, watcher".

There are approaches to reconstruct proto-indo-european language in which the root word is: "oqos" - common in many european languages: oculus (LAT), okulo (EO), ojo (ESP), oko (BOS, BUL, CRO, CZ, POL, SRB, SLK, UKR), øje (DK), вока (BLR), ollo (GAL), окото (MAC), oog (NED), øye (NOR), olho (POR), ochiul (ROM), očesu (SLV), öga (SWE), occhio (ITA), œil (FR), eye (EN). Some of them are quite far away from the original.

Mi pensas, ke "okulo" estas nur prenita el la Latino.

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