What best describes a condition with swelling due to excess fluid in tissues?

The term that best describes a condition characterized by swelling due to the accumulation of excess fluid in the tissues is "edema." Edema occurs when there is an imbalance in the processes that regulate the movement of fluid between blood vessels and surrounding tissues, often leading to puffiness in the affected areas. This condition can be indicative of various underlying health problems, such as heart failure, kidney disease, or inflammation.

In contrast, hematoma refers to a localized collection of blood outside of blood vessels, typically resulting from trauma or injury. A cyst is a closed sac-like structure that may contain fluid, air, or other materials, but it is not necessarily indicative of generalized swelling in the tissues. A lesion denotes an area of tissue that has been damaged or abnormal, which can encompass a variety of conditions but does not specifically imply fluid accumulation. Thus, edema is the most accurate term for the described condition of swelling from excess fluid.