Umbo
{'<entity_0>': 'highest part of each valve of the shell of a bivalve or univalve mollusk', '<entity_1>': 'Umbo'}
[['Umbo', 'description', 'highest part of each valve of the shell of a bivalve or univalve mollusk']]
The <entity_1> (plural umbones or umbos) is the vaguely defined, often most prominent, <entity_0>.
['Anatomical terminology']