Lightning bolt is a natural phenomenon caused by the buildup of electrical charges in the atmosphere. The term 'lightning bolt' can be broken down into three parts: Usain (5 letters), SHAFT (5 letters), and STREAK (6 letters). Usain is a reference to Usain Bolt, the Jamaican sprinter who is the fastest man alive. SHAFT refers to the shape of a lightning bolt, which is long and thin like a SHAFT. Finally, STREAK is a reference to the bright, jagged line that lightning bolts create in the sky.