When you look up an Icelandic noun, the entry never gives you just the word — it gives you the word plus two extra endings, and those endings are not decoration. They are a compact code that tells you exactly which declension the noun follows. The reason is simple: the nominative singular alone is ambiguous. Two nouns can look identical in the dictionary headword and still decline completely differently. The genitive singular and the nominative plural, taken together, resolve that ambiguity. Learn to read those two endings and you can decline a noun you have never seen before; ignore them and you will guess wrong roughly half the time. This page teaches you to decode the citation. The full paradigms themselves live on the dedicated class pages.
The three principal parts
The standard Icelandic citation lists three principal parts: the nominative singular (the headword), then the genitive-singular ending, then the nominative-plural ending. In a dictionary these usually appear as the headword followed by two abbreviated endings:
| Citation | Gender | Nom. sg. | Gen. sg. | Nom. pl. |
|---|---|---|---|---|
| hestur, -s, -ar | kk (m.) | hestur | hests | hestar |
| kona, -u, -ur | kvk (f.) | kona | konu | konur |
| land, -s, lönd | hk (n.) | land | lands | lönd |
Read hestur, -s, -ar as: "the masculine noun hestur, genitive singular hests, nominative plural hestar." Read kona, -u, -ur as: "the feminine noun kona, genitive konu, plural konur." The endings are shown as hyphenated fragments because they replace whatever the headword ends in; when the change reaches into the stem vowel (as in land → lönd), the citation spells the plural out in full so you can see the umlaut.
hestur, -s, -ar (kk)
horse — gen.sg. 'hests', nom.pl. 'hestar'. The -s genitive plus the -ar plural fingerprint the standard strong masculine class.
land, -s, lönd (hk)
land/country — gen.sg. 'lands', nom.pl. 'lönd'. The plural is written out in full because the stem vowel rounds: a → ö.
Why the nominative alone fails
Here is the problem the citation solves. The masculine ending -ur is extremely common in the nominative singular — and it hides at least two different plural classes. Look at three masculine nouns that all end in -ur:
| Citation | Nom. sg. | Gen. sg. | Nom. pl. |
|---|---|---|---|
| hestur, -s, -ar | hestur | hests | hestar |
| gestur, -s, -ir | gestur | gests | gestir |
| dalur, -s, -ir | dalur | dals | dalir |
All three are masculine, all three end in -ur, all three take a genitive in -s. But hestur pluralises in -ar (hestar) while gestur and dalur pluralise in -ir (gestir, dalir). Nothing in the headword tells you which is which. The plural ending is a brute lexical fact you simply have to know — and the citation hands it to you. Guess gestar or hestir and you have produced a word that does not exist.
hestur, -s, -ar (kk)
horse → plural 'hestar'. The -ar plural type.
gestur, -s, -ir (kk)
guest → plural 'gestir', NOT 'gestar'. Same -ur ending, same -s genitive, but a different plural class.
dalur, -s, -ir (kk)
valley → plural 'dalir'. Another -ir masculine. Only the citation's third part tells you to use -ir and not -ar.
The two-part key: strong vs weak
The genitive singular does the first sort. It separates the strong nouns from the weak ones:
- Strong nouns take a consonantal genitive singular — -s (most masculines and neuters) or -ar / -ur / -r (most strong feminines). Their plurals carry real endings: -ar, -ir, -ur, or a bare stem.
- Weak nouns end in a vowel in the nominative singular (-i, -a, -a across the genders) and have a genitive singular that ends in a vowel too — and crucially the genitive often equals the nominative or differs only slightly. Their plurals are vowel-based: -ar, -ur, -u.
Compare a strong and a weak noun of the same gender. Strong masculine hestur has genitive hests (consonant). Weak masculine tími ("time/hour") has genitive tíma (vowel — identical to the accusative and dative). The genitive ending tells you the type at a glance.
kona, -u, -ur (kvk)
woman → gen.sg. 'konu', plural 'konur'. The vowel-final headword '-a' and vowel genitive '-u' mark a WEAK feminine.
auga, -, -u (hk)
eye → gen.sg. 'auga' (no change — the dash means 'same as headword'), plural 'augu'. A weak neuter; the empty genitive slot is itself a fingerprint.
That dash in auga, -, -u is doing real work: it means the genitive singular is identical to the nominative (auga), which only weak nouns do. So the citation auga, -, -u instantly says "weak neuter," and the -u plural confirms it (augu, "eyes").
Five citations, decoded
Put the skill together. Here are five real citations; read each one as a class fingerprint before you ever build a table:
| Citation | Gender / type | What the two endings tell you |
|---|---|---|
| hestur, -s, -ar | kk, strong | -s genitive = strong; -ar plural = the 'hestar' class |
| gestur, -s, -ir | kk, strong | -s genitive = strong; -ir plural = the 'gestir' class (not -ar!) |
| dalur, -s, -ir | kk, strong | identical key to gestur → declines the same way |
| kona, -u, -ur | kvk, weak | vowel genitive -u = weak; -ur plural |
| auga, -, -u | hk, weak | genitive = nominative = weak; -u plural |
Notice that gestur and dalur have an identical key (-s, -ir). That is the whole point: once two nouns share a key, they share a paradigm. You do not memorise a separate table for dalur — you memorise the key -s, -ir once and apply it to every masculine that carries it.
Þetta er hestur. Söðullinn er á hestinum, og taumur hestsins er nýr.
This is a horse. The saddle is on the horse, and the horse's bridle is new. Seeing the genitive 'hestsins' (-s) in use confirms the strong class you read off the citation.
The orthography catch: a written-out plural means umlaut
When a citation writes the plural out in full instead of as a hyphenated ending — like land, -s, lönd — that is a deliberate signal that the stem vowel changes. Here a → ö, the u-umlaut, because the historical plural ending contained a u that rounded the preceding a. The rounded ö is part of the spelling you must reproduce; londur or landir would both be wrong.
land, -s, lönd (hk)
country → plural 'lönd'. The full-form plural in the citation warns you: round the stem vowel a → ö.
Ísland er fallegt, en öll Norðurlönd eru falleg.
Iceland is beautiful, but all the Nordic countries are beautiful. 'Norðurlönd' shows the same a → ö rounding in the plural of '-land'.
Common Mistakes
❌ Looking up only the headword and guessing the plural of 'gestur' as 'gestar'
Incorrect — the citation says 'gestur, -s, -ir', so the plural is 'gestir'. The headword alone cannot tell you the class.
✅ gestur, -s, -ir → gestir
guest → guests. Read the third principal part.
❌ Assuming -ur masculines all pluralise like 'hestur' (-ar)
Incorrect — only some do; gestur and dalur take -ir. The plural is lexical, supplied by the citation.
✅ hestur → hestar, but dalur → dalir
horses vs valleys — same headword ending, different plural class.
❌ Reading 'kona, -u, -ur' as a strong noun because it has a plural ending
Incorrect — the VOWEL genitive '-u' marks it weak; weak nouns have vowel genitives even though they still pluralise.
✅ kona, -u, -ur (weak feminine)
The -u genitive is the tell: weak, not strong.
❌ Ignoring the dash in 'auga, -, -u' and inventing a genitive 'augs'
Incorrect — the dash means the genitive equals the nominative: 'auga'. Don't add a -s.
✅ auga, -, -u → gen. 'auga', pl. 'augu'
eye → eyes. The empty genitive is itself the fingerprint of a weak neuter.
❌ Copying a written-out plural 'lönd' as 'land' in the plural, missing the umlaut
Incorrect — the full-form citation signals a → ö; the plural really is 'lönd'.
✅ land, -s, lönd
country → countries. The rounded ö is part of the word.
Key Takeaways
- An Icelandic noun is cited with three principal parts: nom.sg, gen.sg ending, nom.pl ending — e.g. hestur, -s, -ar.
- The nominative alone is ambiguous: identical headwords belong to different classes (hestur → hestar but gestur → gestir).
- The gen.sg/nom.pl pair is a deterministic class key: nouns sharing the key share the paradigm, so memorising two endings beats memorising whole tables.
- The genitive sorts strong (consonant: -s, -ar) from weak (vowel: -u, -a, or = nom.); the plural names the subclass (-ar, -ir, -ur, -u, or bare).
- A written-out plural in the citation (lönd, börn) warns you the stem vowel mutates — copy the umlaut exactly.
Now practice Icelandic
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Start learning Icelandic→Related Topics
- Icelandic Nouns: Case, Gender, NumberA1 — The big picture of the Icelandic noun: three grammatical genders, four cases marked by endings, number, and a suffixed definite article — plus why you must learn every noun as a three-form citation, not a single word.
- Strong Masculine Nouns: OverviewA2 — The strong masculine declensions — the largest noun group, marked by a genitive singular in -s and a nominative plural in -ar or -ir — with the all-important insight that the -ur of the nominative is an ending, not part of the stem.
- u-Umlaut in Plurals and the Dative PluralA2 — The single most pervasive sound rule in Icelandic noun inflection: a stem 'a' rounds to 'ö' before a following 'u' — most reliably in the dative-plural ending -um (dögum, löndum) and in many bare plurals (barn → börn, land → lönd).