Singular nouns ending with -isi (Masculine or Feminine?)

Question

For preparation for my Italian grammar test tomorrow, I am going through content we've learnt, such as masculine and feminine determination rules. However, I've come up against a dilemma. I distinctly remember my teacher saying that words ending with -isi, like crisi, were feminine, so la crisi, and in plural form it would turn to le crise. However, after searching online, I couldn't find any examples of this. So, is this a proper rule, and are there any more examples of nouns falling under this category?

Answer 1

Well, the plural of la crisi is le crisi. Le crise doesn't exist.

In Italian, some nouns and adjectives are invariant, that is, they have the same form for singular and plural:

il re ▶ i re

la crisi ▶ le crisi

la specie ▶ le specie

There are a lot of different rules and examples:

• Nouns ending with an accented vowel:

le tribù, le città, i maragià, i caffè

Among these we obviously also have monosyllable nouns and adjectives:

i re, le maglie blu, i tè, gli gnu

• Some masculine nouns ending with -a, especially about exotic animals:

i lama, i gorilla, i cobra, i cacatua

Also remind i boia, i paria, i sosia, i vaglia, whereas pigiama has both the invariant form i pigiama and the normal form i pigiami.

• Shortened nouns

le auto, le bici, le moto, i cinema

• Some feminine nouns ending with -ie

le barbarie, le serie, le specie, le congerie, le temperie

• Adjectives and feminine nouns ending with -i

numeri pari, squadre dispari, le ipotesi, le analisi, le nevrosi

• Nouns composed of two verbs or a verb and a feminine singular noun:

i saliscendi, i posacenere, i va e vieni, gli scioglilingua

• Some borrowed foreign nouns:

gli sport, gli chalet, i würstel, i toreador

• Some adjectives indicating colors:

stoffe amaranto, pareti lilla, lampade rosa, guanti viola, sfumature indaco

• The adjective arrosto

due polli arrosto

• Also in the sequence color adjective + related noun:

camicie verde bottiglia, copertine grigio topo

• Compound adjectives with the prefix anti- + a noun

prodotti anticellulite, sostanze antigelo

• Some compound adjectives, originally adverbial phrases, where the second element is -bene, -modo, -poco

ragazze perbene, uomini ammodo, case dappoco

• The adjective avvenire ‘futuro’, coming from the adverbial phrase a venire

i mesi avvenire, le giornate avvenire.

Answer 2

Words in -si are invariant, so the plural of la crisi is le crisi, not *le crise.

There are more examples of this kind of noun here. (archived)