(mycology) A bump or protrusion on the top of the cap.
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(biology) A knoblike protuberance arising from a surface, as the prominence near the hinge of a bivalve shell or the raised area in the center of the cap of a mushroom.
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(anatomy) A small projection at the center of the outer surface of the eardrum.
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Something resembling this.
The elevation beside the hinge on each half of a bivalve shell.
The prominence on the eardrum at the point of attachment of the malleus.
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A small anatomical projection on a surface, such as that on the inner surface of the eardrum at the end of the manubrium of the malleus, corresponding to the most elevated point of the eardrum.
They protected themselves in battle with a large wooden or wicker shield, the centre of which was ornamented with an iron boss (umbo).
The ventral valve is usually the larger, and in many genera, such as Terebratula and Rhynchonella, has a prominent beak or umbo, with a circular or otherwise shaped foramen at or near its extremity, partly bounded by one or two plates, termed a deltidium.
The beak or umbo of each valve is prominent and rounded, and a number of sharp ridges and furrows radiate from the apex to the free edge of the shell, which is crenated.