Single; not complex or compound. That idea which represents one determinate thing, is called a singular idea, whether simple, complex or compound.

In grammar, expressing one person or thing; as the singular number. The singular number stands opposed to dual and plural.

Particular; existing by itself; unexampled; as a singular phenomenon. Your case is hard, but not singular.

Remarkable; eminent; unusual; rare; as a man of singular gravity, or singular attainments.

A particular instance.