E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Punc’tual.
No bigger than a point, exact to a point or moment. (Latin, ad punctum.) Hence the angel, describing this earth to Adam, calls it “This spaclous earth, this punctual spot”—i.e. a spot no bigger than a point. (Milton: Paradise Lost, viii. 23.)
