NCIt definition : A collection of fluid in a body cavity, which may be the result of a non-neoplastic
disorder (e.g. heart failure) or a tumor (e.g. carcinoma of the lung).;
Alternative definition : NCI-GLOSS: An abnormal collection of fluid in hollow spaces or between tissues of
the body. For example, a pleural effusion is a collection of fluid between the two
layers of membrane covering the lungs.; CDISC: Abnormal collection of fluid in a body cavity.;