MeaningUsed to show that one thing is the reason for another thing. It means "so" or "for that reason".
HistoryThis word is very old and appears in the Bible. It is made from two small words put together: "לָ" (la), which means "for", and "כֵן" (ken), which means "so" or "this way". So together, it means "for this reason".
It was raining, so we stayed at home.