Ordinal numbers

First, Second, Third

Higher up: þrítugasti (30.), fertugasti (40.), fimmtugasti (50.), hundraðasti (100.). Compounds join with og: tuttugasti og fyrsti.

They behave like adjectives

Icelandic adjectives have two sets of endings. The weak set is the one used after the definite article, a demonstrative or a possessive - and it is the set ordinals normally take, because the third floor is definite by its nature:

Plural is fyrstu in every gender and case. fyrstur also keeps a strong set for predicative use: Hann kom fyrstur (he came first).

In the tens ordinals the stem vowel follows the ending. Where the weak ending is -i or -a the stem keeps its a (tuttugasti, tuttugasta); where the ending is -u the a becomes u - feminine accusative, dative and genitive, and the whole plural: tuttugustu, hundruðustu. They are also built on the -tugur stem rather than on the cardinal: þrjátíu - þrítugasti, fjörutíu - fertugasti.

annar is the exception

annar does not follow the weak pattern - it declines strongly, and it also means other, another:

Where you meet them

• Floors: Ég bý á þriðju hæð.
• Dates: sautjándi júní.
• Listing points: í fyrsta lagi, í öðru lagi.
• Inside the weekday names themselves: þriðjudagur is the third day and fimmtudagur the fifth, counting from Sunday. The count breaks at Wednesday, which is miðvikudagur, mid-week day: the older pagan names (týsdagur, óðinsdagur, þórsdagur) were pushed out around 1100 at the initiative of Bishop Jón Ögmundarson of Hólar.