= Terminal object
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A <terminal object> $1$ of a <category> receives exactly one <morphism> $X\to1$ from every object $X$. Any two terminal objects are uniquely isomorphic by composing their unique connecting maps.
A <singleton> is terminal in the <Category of sets>, and the trivial <group> is terminal among <groups>. The empty <set> is not terminal, because no function from a nonempty set to it exists. An object that is both initial and terminal is a <zero object>; this occurs for the trivial group but not in the category of all sets.
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