Noah Webster
Singular
SIN'GULAR, adjective [Latin singularis, from singulus, single.]
1. Single; not complex or compound. That idea which represents one determinate thing, is called a singular idea, whether simple, complex or compound.
2. In grammar, expressing one person or thing; as the singular number. The singular number stands opposed to dual and plural.
3. Particular; existing by itself; unexampled; as a singular phenomenon. Your case is hard, but not singular
4. Remarkable; eminent; unusual; rare; as a man of singular gravity, or singular attainments.
SIN'GULAR, noun A particular instance. [Unusual.]