ブレ is a common terminology in Sakuga. It means shake. ブレ is generally associated with an intensity: (弱weak, 中 middle, 強 strong). Not to be confused with Blurブラー.
Types of Bure:
Line Bure (線ブレ) refers to a line boil effect that is useful in cases such as shivering, shaking, vibrating, and more.
Camera Shake (画面ブレ)
Concentration Line Blur (集中線ブレ)