This is the 4430th most frequent Polish word.
jedynka
"Jedynka" means "number one," "grade one (in school, often a failing grade)," or "channel one (on TV/radio)."
In this sentence, 'jedynka' refers to the grade 'one,' which in the Polish education system often indicates the lowest or failing grade.
Mam jedynkę z matematyki.
I have a one in mathematics.
Here, 'jedynka' is used as a colloquial term for the first (front) tooth, indicating its position or order.
Zęby mojego dziecka zaczynają rosnąć od jedynki.
My child's teeth start growing from the first tooth.
In this context, 'Jedynka' is a nickname for the first television channel in Poland, commonly used among viewers.