What is relation between Lead Time and Safety Stock

Suppose you are pizza addict. You love to eat 1 pizza daily. If you ordered pizza on 4 PM and you got delivery at 5 PM then difference 1 hour is called Lead Time. 
Lead Time means delay between time of placing an order and time of receiving the ordered quantity.Suppose you came to know that pizza-hut would be closed for next 3 days. It means you cannot order pizza on those 3 days. Since you are pizza addict so you need 1 pizza daily. Now you ordered 3 extra pizza before those 3 days and kept in microwave. These 3 pizzas are your safety stock. Safety stock means minimum stock so production does not stop due to lack of raw material.