A bodily cavity, especially one having bony walls, especially one in the sinuses.
A chamber in the mammalian kidney through which urine passes.
The outermost whorl of flower parts, comprising the sepals, which covers and protects the petals as they develop.
The crown containing the viscera of crinoids and similar echinoderms, entoprocts, and the polyps of some cnidarians.
A flattened cap of neuropil in the brain of insects.
A funnel-shaped expansion of the vas deferens or oviduct of insects.