كَانَ to be; to exist; to happen, occur, take place

كَانَ الطّعَامُ لَذِيذاً the food was delicious

كَانَ لَهُ صَدِيقٌ he had a friend; he used to have a friend

كَانَ يَلْعَبُ he was playing; he used to play

لِيَكُنْ، فَلْيَكُنْ let it be (done), fiat, OK, all right