This is the noise English speakers say a rooster makes — the adult male chicken that crows, often at dawn. It is not a word you unpack for meaning; it is a sound written down, the way a child writes what they hear. Though actually, no bird says these syllables: English just chose this stretch of sound, and other languages hear the same crow differently. You will meet it in picture books, comics, and jokes far more than in grown-up talk. People also use it as a noun for the crow itself. It is playful, not formal, and nobody is impressed if you use it in an essay — unless you are quoting a story.