This is the 244th most frequent Polish word.
jednej
"Jednej" means "of one" or "to one" (genitive or dative singular form of "jedna").
Indicates 'one' in a feminine singular form within the genitive case.
Mam jedną siostrę, ale tylko jednej się zwierzam.
I have one sister, but I confide only in one.
Refers to 'one' in a feminine singular form within descriptive context.
Historia tej jednej nocy zapadła mi w pamięć.
The story of that one night stayed in my memory.
Used as 'one' in a feminine singular form referring to a specific entity.