Origin of surd
Examples from the Web for surd
On the one hand Aristotle by his doctrine of matter admitted a surd into his system.
Surdimū′tism, the condition of being deaf and dumb; Surd′ity, want of sonant quality.
The problems have a surd or irrational element in them; and to solve them would be to bring reason into collision with itself.
The terms sonant and surd are, in a scientific point of view, the least exceptionable.A Handbook of the English Language|Robert Gordon Latham
Again, he points out that the surd aspirate h is heard in some languages, but is hardly audible in others.All About Coffee|William H. Ukers