Very early in learning a language, you’re going to learn numbers and days of the week. If you’re going to memorize such things, you might as well get a few others words from the experience and help yourself remember which day is which.
|S||niedziela||nie + dzieło (no + work)|
|M||poniedziałek||po + niedziałek (after + Sunday)|
|T||wtorek||wtórny (secondary) Second day after Sunday|
|W||środe||środek (middle) Middle of the week|
|Th||czwartek||czwarty (fourth) Fourth day after Sunday|
|F||piątek||piąty (fifth) Fifth day after Sunday|
|Sa||sobota||seems derived from the word Sabbath or Shabbat|