What term describes sideways movement in a plant or soil?

The term that accurately describes sideways movement in a plant or soil is "lateral movement." This term specifically refers to movements that occur horizontally or side to side, as opposed to vertical movement, which would involve upward or downward shifts. In the context of soil, lateral movement can pertain to the flow of water or nutrients moving through the soil profile in a sideways direction, as well as roots spreading outwards.

Translocation, on the other hand, typically refers to the movement of substances within a plant, such as the transport of nutrients or water through vascular tissues. Vertical movement focuses instead on upward or downward shifts, which are not relevant when discussing sideways motion. Radial movement relates to motion radiating out from a central point, which also does not accurately capture the concept of lateral, or side-to-side, movement. Thus, lateral movement is the correct term for describing this specific horizontal motion in plants or soil.