I have read several dictionaries and now feel confused. I guess that: (1)For anarthrous(without article) singular noun, it means “each”; (2)For articular singular noun, it means “the whole”.
But for anarthrous and articular plural noun, I cannot tell the difference.
It’s rather subtle, and may not be easy to grasp at first, but what it comes down to is the difference between predicative and attributive use. Predicative has no article: ἔπεσε πᾶν “it all fell down” i.e. it fell down in its entirety, πάντες απῆλθον “everyone left” i.e. they left, all of them. Attributive has the article, and is less usual and more difficult: τὸ πᾶν ἔπεσεν “the whole fell" (e.g. the universe).
Similarly when there’s a noun: e.g. πᾶσαι αἱ γυναῖκες κακαί “all women are bad” (women are bad, all of them), or ἡ γυνὴ κακὴ πᾶσα “the woman is all bad” (the woman is bad, all of her). This is the predicative use, which is more normal than the attributive.