I guess American Football and to some extent Baseball have sets of terms I, for one,
have absolutely no idea what the commentators are talking about. Cricket is all about
friendly warfare with various reasons for it to be stopped and then, usually, everyone takes refreshments. Those reasons are invariably bad light or rain and the term offered the light refers to the umpires (two on the pitch and one monitoring on video for the big games such as the Tests) who have a light meter in their pocket. They will take a reading and confer between themselves and if it's going darker (such as a dark cloud or towards the end of the day) they will then offer the batsmen who could then take the light or decline the light and carry on batting. When you think that a cricket ball is a solid object and fast bowlers(pace bowlers) can sometimes reach delivery speeds of 100 mph so to have one of these 'missiles' bearing down with the sole intent of knocking your head off before it also hits the wickets, you can see why light can be a sensitive topic. There are various points when there has to be a halt such as Lunch and afternoon Tea though if there has been extensive bad light or rain these can be waived and play continued.
It has to be the most civilised game in all the world.