DONUT and DOUGHNUT are not homonyms, homophones, homographs or heteronyms. They are alternate spellings.
Plaintiff has been using MINI DONUT FACTORY for a chain of stores in Illinois since 2008. It now has a federal registration. Defendant opened a donut store in Tampa under the name MINI DOUGHNUT FACTORY. Defendant, apparently a domainer turned donut purveyor, obtained the domain name MiniDonutFactory.com which it redirects to MiniDoughnut Factory.com. Plaintiff uses MiniDonutFactories.com.