on: (upon) sur (adj.) sura; (contiguity) an; on account of: pro; on this side: cis; on behalf of: por; to go on foot: ped-irar; on high: supre, ye la supro (di); on purpose: intence, vole; on that day: ta-jorne, ca-die; on the left: sinistre; to swear on his hono(u)r: jurar per sua honoro; to be on guard: gardar su; on credit: kredite, ye kredito; on further enquiry: pos plu ampla (od, plusa) informo o inquesto; deliberate on: deliberar pri; on the whole: sume; count on someone: fidar ad ulu; have pity on: kompatar (ulu); on flame: flam-oza; on hand: esar ibe, esar hike; (goods) en butiko; on the way: dum voyo; on my arrival: ye mea arivo; an entering: kande me en-iris; on examination: pos exameno; read on: lektar pluse; on ! ad-avane! march on: marchar ad-avane; avancar; far on in the night: tre tarde; and so on: e tale pluse; play on: durar ludar, plear; live on: vivar ankore; a ladder on the (against the) wall: skalo an la muro; a house on the river: domo an la rivero; (cf. suffix -iz-).
onager: onagro.
onanism: onani-(ad)o; to commit o.: (intr.) -ar.
once: (in counting) un-foye: (on a certain occasion) ul-tempe; ul-die; once upon a time: olim; at once: (immediately) quik; (at the same time) samtempe.
one: (indefinite pronoun) on; (numeral) un; (one person) unu; (adj. indicating unity) una; (unit) un-o, -ajo; one of the two: l’una o l’altra; to make one: un-igar; neither one nor the other: nek l’una nek l’altra, nula de la du; that is all one: to esas sama (od, identa); one person alone cannot: una sola ne povas; one by one: un-ope; one-eyed: (person) tuert-a, -(ul)o; oneness: un-eso; one-sided: (biassed) partis-ala, -ana; ne-yusta; oneself: su (ipsa); to be at one: konsentar, konkordar; one-colo(u)red: un-kolora; (cf. unika).
onerous: opresanta, -iva, -ema; (costly) kust-oza.
onion: onyono.
only: nur (cf. sola, unika); o. love inspires him: nur l’amo inspiras lu; o. God can: nur Deo povas; not o.: ne nur, ma anke: he o. was there: il sola (od, nur) esas ibe; o. child: unika filio.
onomatopoeia: onomatopeo.
onset, onslaught: atako, asalto.
ontogenesis: ontogenezo.
ontology: ontologio.
onus: karg-ajo; devo.
onward: (ad-)avane; (adj.) avana, avanc-anta, progres-anta; to go o.: avancar.
onyx: onixo.
oolite: oolito.
ooze: (intr.) exudar, (intr.) flu-etar.
ooze: (slime, silt) slamo.
opacity: opak-eso.
opal: opalo.
opalesce: opalecar (intr.).
opalescence: opalec-(ad)o.
opalescent: opalec-anta, opal-atra; o. glass: opalec-anta vitro.
opaline: opal-atra.
opaque: opaka.
open: apertar; (cf. des-klozar); (a ball, dance, fire) komencar (cf. inaugurar); (a bottle) des-stopar.
open: (not shut) apertita, des-kloz-ita; (frank) sincera; (free, unrestricted) libera; (of a question) ne-decid-ita; (of weather) ne-severa, dolca; (exposed) expozita (ad); o.-handed: jeneroza; o.-hearted: grand-anma; sincera; o.-eyed: vigil-anta; o.-mouthed: be-anta-a, -e; kun boko apertita; o. to an engagement: libera por engajar su; half-opened: mi-apert-ita; wide o.: tote apertita; in the o. air: en libera aero; in the o. sea: en meza o larja maro; in the o. day: en meza jorno, en granda lumo; o. shame: publika shamo; to keep o. house: havar la hemo, la domo apertita por (od, ad) la publiko.
opener: (instr.) apert-ilo; (person) -isto.
opening: (chapter, etc.) un-esma; komenc-anta.
opening: (act of o.) apert-o; (aperture) apert-uro (cf. brecho; fend-uro; truo); (commencement) komenco; (first appearance) debuto; (opportunity) okaziono; chanco; (for sale of goods) debit-eyo.
openly: aperte, ne-cel-ate, sincere, honeste, kandide.
opera: oper-o; o. house: -teatro; o. glass: bi-lorn-eto.
operate: (surg., finan., milit.) operacar; (work) (intr.) agar, efikar, funcionar, (in stock markets) spekular.
operation: (math., surg., milit., fin.) operaco; (in gen.) ago, efiko, funcion-ado, procedo.
operative: (n.) mestier-isto, laboristo, fabrik-anto, -isto; (adj.) ag-iva, (efficacious) efik-anta, -iva, -ema.
operculum: operkulo.
operetta: oper-eto.
ophicleide: ofikleido.
ophite: ofito.
opthalmia: oftalmio; -mic: okul-ala.
opthalmology: oftalmologio.
opthalmoscope: oftalmoskopo.
opiate: opiato, narkot-ig-ivo.
opine: (intr.) opinionar, expresar (sua) opiniono.
opinion: opiniono; to be of the o.: -ar, havar ta opiniono; to have high o. of: bone o favore opinionar pri (ulu, ulo); in the o. of: segun la opiniono di.
opinionated: obstin-anta, -ema.
opium: opiumo.
opodeldoc: opodeldoko.
opossum: sarigo.
opponent: antagonisto, adverso; opozanto, -ero (collect.) -ant-aro.
opportune: oportuna; -ness: -eso.
opportunism: oportun-ismo.
opportunist: oportun-isto, -ista.
