A harmonic trap is a trap in which the trapped objects (e.g., atoms) are pushed toward the center of the trap with a force proportional to their distance from the center of the trap. The motion of particles in a harmonic trap is analogous to the motion of a mass attached to a spring around the spring's equilibrium position. It is convenient to use harmonic traps in experiments because it is straightforward to calculate the motion of particles in analogy to the mass on a spring.
