From Middle English dogge tothe; equivalent to dog +‎ tooth.

dogtooth (plural dogtooths or dogteeth)

(plural only "dogtooth") A canine tooth. (Can we add an example for this sense?)
(architecture) An ornament common in Gothic architecture, consisting of pointed projections resembling teeth.
- 1851, John Ruskin, “The Edge and Fillet”, in The Stones of Venice, volume I (The Foundations), London: Smith, Elder, and Co., […], →OCLC, § IV, page 260:
  This arch is the side of a niche from the tomb of Can Signorio della Scala, at Verona; and the value, as well as the distant expression of its dogtooth, may be seen by referring to Prout's beautiful drawing of this tomb in his "Sketches in France and Italy."
Synonym of houndstooth