Teaching defense in basketball requires instruction on many different defensive strategies. A key attribute any team defense must have is communication. Communication is important when calling out "switches" to teammates. What a "switch" is on defense is that a defensive player gets "switched" onto another offensive player when it is more convenient for them to defend them. This is communicated by calling out the word switch. Basketball IQ is incredibly important as well in teaching defense because a defense must adjust in-game because the opposing offense should have a scouting report of the defense's strengths and weaknesses.
There are many types of defense in basketball, including the 3-2 zone and 2-3 zone defense. These types of defense require all five players moving and rotating to cover up potential weak points in the defense. The five defenders must move as one unit to prevent the other team from creating offensive opportunities. This is called defensive rotations. It's a concept that when done right, is a key advantage on defense and can potentially lead to turnovers. There is also man defense in which each defender is assigned an offensive player to defend. When a defensive player gets beat off the dribble by an offensive player, another defender must rotate to help stop the offensive player. This is otherwise known as help defense.
Forcing turnovers is one of the most important parts of playing defense and therefore it must be coached well. Keeping players from reaching when trying to force a steal or fouling underneath the basket can be the difference in a game. Well disciplined teams often play solid defense and this is important to preach in the coaching of defense.