This sponge has great elasticity, returning to its original shape after being pressed.

elasticity 是名词，由形容词 elastic（有弹性的）加上名词后缀 -ity 构成，表示"弹性"这种性质。这个词根来自希腊语 elastos（可伸展的），描述物体受压变形后能恢复原状的能力。