Vasond stream and Borloka

Why are all these -d letters at the end of local names (Pottyand, Szilosd, Vasond, Tompád, Béd)? According to linguists, in the old Hungarian language letter -d was a diminutive form. Szilosd got its name from the Wych Elm (szil=elm), Vasond (Iron st.) probably from the ferruginous springs. At the meeting of the two streams a fen was formed. Its characteristic plants are Creeping Willow, Marsh Grass-of-Parnassus, Broad-leaved Cottongrass, Early Marsh Orchid. Not far in the valley there is a mineral water spring.