1) The quality of serous fluids 2) Watery consistency 1) Water 
• (n.) A thin watery animal fluid, as synovial fluid and pericardial fluid. • (n.) The quality or state of being serous.
1. The quality or state of being serous. ... 2. <physiology> A thin watery animal fluid, as synovial fluid and pericardial fluid. ... See: serous. ... Origin: Cf. F. Serosite. ... (28 May 1998) ... 
(sēr-os´ĭ-te) the quality of serous fluids.
Se·ros'i·ty noun [ Confer French serosité . See Serous .] 1. The quality or state of being serous. 2. (Physiol.) A thin watery animal fluid, as synovial fluid and pericardial fluid. 
Type: Term Pronunciation: se-ros′i-tē Definitions: 1. A serous fluid or a serum. 2. The condition of being serous. 3. The serous quality of a liquid.
serosity 1. Slang for serious or seriousness: 'We must consider the serosity of the situation.' 2. Bureaucratic language: A growing number and volume of imagined consequences driving a decision or demand for hasty action.