1
Reign

• 1. Reign is a verb meaning to rule, esp. as a
  king
• EX As long as they dont get lazy, the Party
  will REIGN in Oceania forever
• EX In the Terminator and Matrix movies, the
  machines REIGN in the future

2
Reign

• 1A. Reign is also a noun referring to a period
  of rule, esp. of a king or sovereignty
• EX When Queen Elizabeth dies, Prince Charles
  will begin his REIGN as king of England
• EX The REIGN of the dinosaurs ended with the
  mammals

3
Rein

• 2. Rein is a verb meaning to guide or control
  an animal (usually a horse) by a harness fastened
  about the head
• EX REIN your horse through the gate and we can
  tie them up over here
• EX You have to know how to REIN your horse
  better if you want to win the race

4
Rein

• 2A. Rein (usually reins) is the leather strap
  attached to the head harness of a horse, which is
  used to direct or control the animal
• EX If you pull on the left REIN, the horse will
  turn left
• EX When the rider dropped the REINS, the horse
  took off for the hills

5
Rain

• 3. Rain is a noun meaning a continuous, heavy
  descent of something, usually water from the
  sky/clouds
• EX The RAIN soaked through his clothes and he
  caught a cold
• EX The archers sent a RAIN of arrows falling
  onto the enemy soldiers

6
Rain

• 3A. Rain is also a verb meaning to fall or
  descend upon, most often with water
• EX It will RAIN all day tomorrow so we cant
  have the picnic
• EX The crowd planned to RAIN insults upon the
  politician
• EX The boxer wants to RAIN punches on his
  opponent