Nouns, Articles, and Cases
Esperanto nouns — the -o ending, la article, plural -j, accusative -n, and using prepositions for other cases.
Nouns in Esperanto
All Esperanto nouns end in -o. This is absolute and invariable — there are no exceptions. Any word functioning as a noun carries the -o ending.
libro (book)
amiko (friend)
urbo (city)
lando (country)
amo (love)
verdo (greenness — even abstract qualities are nouns with -o)
Nouns have no grammatical gender in Esperanto. A libro is neither masculine nor feminine — it is simply a book. When you want to specify a natural gender of an animate being, use:
- The suffix -in- for feminine: instruisto (teacher) → instruistino (female teacher)
- The prefix ge- for mixed-gender groups: gepatroj (parents), gestudenтoj (students, mixed)
- The base word is either gender-neutral or conventionally referring to a male in some cases
The Definite Article: la
The definite article is la (the). It is completely invariable — it never changes for number, case, or gender.
| Context | Esperanto | English |
|---|---|---|
| Singular | la libro | the book |
| Plural | la libroj | the books |
| Accusative singular | la libron | the book (as object) |
| Accusative plural | la librojn | the books (as object) |
| With adjective | la bona libro | the good book |
There is no indefinite article. The absence of la signals indefiniteness:
- libro = a book / some book
- la libro = the book (specific, known)
When to use la:
- When the noun is specific and known to both speaker and listener
- When it has been mentioned before ("the book" = that specific book we talked about)
- With unique referents: la suno (the sun), la luno (the moon), la tero (the Earth)
- With superlatives: la plej bona (the best)
When not to use la:
- First mention of an unknown specific: Mi havas libron. (I have a book.)
- Generic/category statements: Mi amas kafon. (I love coffee — coffee in general)
- After most prepositions when generality is intended
The Plural: -j
Plurals are formed by adding -j to the noun ending -o:
| Singular | Plural | Meaning |
|---|---|---|
| libro | libroj | books |
| amiko | amikoj | friends |
| urbo | urboj | cities |
| homo | homoj | people |
The -j also attaches to adjectives that modify a plural noun (adjective-noun agreement):
| Singular | Plural |
|---|---|
| bona libro | bonaj libroj |
| granda urbo | grandaj urboj |
| la malnova domo | la malnovaj domoj |
The article la does not change:
- la libro → la libroj (not la libroj)
- la bona libro → la bonaj libroj
The Accusative: -n
The accusative marks the direct object of a verb and is formed by adding -n.
Accusative for Direct Objects
| Sentence | Notes |
|---|---|
| Mi legas libron. (I read a book.) | libron = direct object of legas |
| Li vidas ŝin. (He sees her.) | ŝin = accusative of ŝi |
| Ni manĝas bonajn pomojn. (We eat good apples.) | Both adjective and noun take -n; plural adds -j too → -jn |
| Ĉu vi konas la instruistinon? (Do you know the teacher?) | Accusative on singular with article |
Agreement chain: When a noun takes the accusative -n, all adjectives (and the article, though la doesn't change) agree. In practice: noun -n, adjective -n + -j if plural:
| Singular | Plural | |
|---|---|---|
| Nominative | bona libro | bonaj libroj |
| Accusative | bonan libron | bonajn librojn |
| With article (nom.) | la bona libro | la bonaj libroj |
| With article (acc.) | la bonan libron | la bonajn librojn |
Accusative for Direction
The accusative -n also marks the direction of movement (where something is going), distinct from position (where something is):
| Position (no -n) | Direction (-n) |
|---|---|
| Mi estas en la ĉambro. (I am in the room.) | Mi iras en la ĉambron. (I go into the room.) |
| Li estas hejme. (He is at home.) | Li iras hejmen. (He goes home.) |
| La libro estas sur la tablo. (The book is on the table.) | Mi metas la libron sur la tablon. (I put the book on the table.) |
Direction with city/country names:
- Mi vojaĝas Londonon. (I am traveling to London.) — accusative of direction, no preposition needed
- Ni iras Japanion. (We are going to Japan.)
Accusative for Time Expressions
The accusative can mark a duration or a specific time point:
| Expression | Meaning |
|---|---|
| Ŝi laboris la tutan tagon. | She worked the whole day. |
| Ni atendis longan tempon. | We waited a long time. |
| Mi dormis du horojn. | I slept two hours. |
| Li revenos la venan lundon. | He will return next Monday. |
Expressing Other Cases with Prepositions
Esperanto has only two cases: the nominative (unmarked) and the accusative (-n). All other grammatical relationships are expressed with prepositions:
| Relationship | Preposition | Example |
|---|---|---|
| Genitive (of, 's) | de | libro de Ana (Ana's book) |
| Dative (to, for) | al | Mi donis libron al Ana. (I gave a book to Ana.) |
| Instrumental (with, by means of) | per | Mi skribas per krajono. (I write with a pencil.) |
| Comitative (with, together) | kun | Mi iris kun Ana. (I went with Ana.) |
| Locative (at, in) | en, sur, ĉe, apud, etc. | Mi estas en la domo. |
| Ablative (from, away from) | de, el, for | Veni el la urbo (to come out of the city) |
Key Prepositions Reference
| Preposition | Core Meaning | Extended Uses |
|---|---|---|
| de | of, from, by | possession, origin, passive agent |
| al | to, toward | destination, recipient (indirect object) |
| en | in, into (+ acc) | location inside; movement into |
| el | out of, from | origin from inside |
| sur | on, onto (+ acc) | surface location; movement onto |
| sub | under | beneath |
| super | above | over, above |
| antaŭ | before, in front of | temporal and spatial |
| post | after, behind | temporal and spatial |
| ĉe | at, by, near | proximity; at (someone's place) |
| apud | next to, beside | spatial proximity |
| inter | between, among | spatial and metaphorical |
| tra | through | movement through |
| trans | across, beyond | crossing |
| kontraŭ | against, opposite | opposition, facing |
| pri | about, concerning | topic |
| pro | because of, due to | cause/reason |
| por | for, in order to | purpose, intended recipient |
| per | by means of, with | instrument |
| kun | with, together with | accompaniment |
| sen | without | absence |
| ĝis | until, up to | temporal and spatial limit |
| dum | during, while | temporal coincidence |
| anstataŭ | instead of | substitution |
| krom | except, besides | exclusion or addition |
| laŭ | according to, along | conformity; spatial along |
| malgraŭ | despite | concession |
| spite | in spite of | defiant concession |
| da | of (quantity) | links quantity to substance |
The da vs. de Distinction
This is one of the trickiest points for new learners:
- de = genitive "of" (possession, origin, identity): glaso de akvo can feel odd — it's a glass from water?
- da = "of" after a quantity expression: glaso da akvo (a glass of water)
| Correct | Meaning |
|---|---|
| glaso da akvo | a glass of water (quantity) |
| kilogramo da sukero | a kilogram of sugar |
| multo da homoj | many people |
| kiom da mono? | how much money? |
| iom da kafo | some coffee |
Rule: Use da after any word expressing amount or measure: iom, multo, kiom, tiom, glaso, kilogramo, litro, paro, grupo, etc.
Use de for possession and other relationships: la libro de Ana, veni de Parizo, la kanto de birdoj.
Word Order and the Accusative
One of the great benefits of the accusative -n is that Esperanto can use flexible word order for emphasis, and the grammatical meaning remains clear:
| Word Order | Meaning |
|---|---|
| Mi legas libron. | I read a book. (neutral) |
| Libron legas mi. | It is a book that I read. (emphasis on "book") |
| Legas libron mi. | I do read a book. (emphasis on action) |
| Libron mi legas. | A book is what I'm reading. (topic + comment) |
All four sentences mean "I read a book" but with different emphasis. The -n on libron always marks it as the object, regardless of position.
This is fundamentally different from English, where word order determines grammatical role (subject-verb-object must be maintained).