This is the 2580th most frequent Polish word.
soli
"Soli" is the genitive singular or nominative plural form of "sól," meaning "salt" in English.
The word "soli" is the genitive case form of "sól," as well as the dative case form. Here it is used in the dative case, as per the grammatical rules in this sentence structure.
Dodaj trochę soli do zupy.
Add some salt to the soup.
"Soli" is used here in the genitive case to indicate a specific quantifiable lack.
Wczoraj zabrakło nam soli.
We ran out of salt yesterday.
"Soli" metaphorically plays on phonetic similarity to the English word "soul".