Emily Dickinson Lexicon

signal, adj. [Fr. 'to distinguish'.]

1. Striking; remarkable; eminent; notable; conspicuous.
2. Rare; matchless; extraordinary; exceptional; of such proportion; [fig.] valuable; essential; crucial.
3. Unique; [word play on “single”] singular; one of a kind.
4. Attractive; attention-getting; [fig.] bright; easily noticed.