Under flow can be referred to as a variety of synonyms depending on the context of the situation. For instance, the term "subsurface flow" is often used in the field of hydrology to describe the process of water being absorbed into the soil and directed underground. Similarly, "groundwater flow" can be used to describe the same phenomenon. In the context of technology, "undercurrent" describes a similar process in which a low-level, continuous flow of electricity powers a device or system. Other synonyms for under flow include "below the surface flow," "subterranean flow," and "low-level flow." It's essential to choose the appropriate synonym to ensure clear communication.