Ventricles

n. cavity in an organ or a body; one of the two main chambers of the heart; any of the four cavities of the brain

In anatomy, a ventricle is a part of the body filled with fluid: Ventricle (heart), the pumping chambers of the heartVentricular system in the brainVentricle of the larynx, a structure in the larynx Penile ventrical = seminal fluid holder
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Ventricles The two chambers of the heart that are involved in pumping blood. The right ventricle pumps blood into the lungs to receive oxygen. [more]Ventricles - Community and Resources

Noun
1. one of four connected cavities in the brain; is continuous with the central canal of the spinal cord and contains cerebrospinal fluid
(hypernym) cavity, bodily cavity, cavum
(hyponym) fourth ventricle
(part-holonym) brain, encephalon
(part-meronym) spinal fluid, cerebrospinal fluid
2. a chamber of the heart that receives blood from an atrium and pumps it to the arteries
(synonym) heart ventricle
(hypernym) chamber
(hyponym) left ventricle

Chambers of an organ. For example, the four connected cavities (hollow spaces) in the central brain or the four chambers of the heart.