What term refers to the coming together of entities like blood cells or diseases?

The term "aggregation" specifically refers to the process where entities, such as blood cells or pathogens, cluster or group together. In the context of blood cells, aggregation can be an important physiological response, such as when platelets come together to form a clot during injury to a blood vessel. This is crucial for maintaining hemostasis and preventing excessive bleeding.

The term is widely used in various medical and biological contexts, particularly in hematology and immunology, where the behavior of cells in groups can influence the function of the immune system or the clotting process. For example, in the presence of certain stimuli (like injury or infection), blood cells may aggregate to effectively respond to the situation.

Other options describe different but related concepts. "Accretion" typically refers to the gradual accumulation or increase of something in size or quantity, which doesn't specifically capture the concept of entities coming together in the same way as aggregation. "Adhesion" refers to the sticking together of different substances or entities, such as cells sticking to surfaces or each other, which conveys a different type of interaction. "Accumulate" focuses on the process of gathering or collecting over time rather than the immediate coming together of entities in a cohesive manner.