This is the 18040th most frequent Polish word.
żytnicki
"Żytnicki" is a Polish surname and does not have a specific definition beyond being a proper noun.
In this sentence, 'Żytnicki' is used as a proper noun, specifically a surname.
Pan Żytnicki mieszka w Warszawie.
Mr. Żytnicki lives in Warsaw.
Here, 'żytnicki' is used as an adjective describing the type of bread made from rye.
Chleb żytnicki jest bardzo zdrowy.
Rye bread is very healthy.
In this context, 'Żytnicki' is used as a proper noun to refer to a person by surname.