Plain English Meaning

The shock absorbers built into the landing gear legs. They squash down on landing to soak up the impact, then slowly extend again, so the airplane and the people inside don't feel a hard jolt.

Full Definition

Shock struts are landing gear components that absorb and dissipate the impact loads of landing and the bumps of taxiing. The most common design is the air/oil (oleo-pneumatic) strut, a sealed cylinder containing compressed nitrogen or air above hydraulic fluid. On compression, the fluid is forced through a small orifice, converting the energy of impact into heat and cushioning the airframe.