From Old Danish trodhe, trædhe, from Old Norse troða, from Proto-Germanic *trudaną (“to tread”), cognate with Norwegian Bokmål tre, Swedish träda, English tread, German treten. The modern Scandinavian form with e-vocalism is influenced by Middle Low German treden. The o-vocalism is retained in Norwegian Nynorsk trå and Danish tråde. Possibly, the verb may also have absorbed the related verb Old Norse treðja (“to tread down”), from Proto-Germanic *tradjaną.
træde (imperative træd, infinitive at træde, present tense træder, past tense trådte, perfect tense er/har trådt)
From Old Norse *þræða, from Proto-Germanic *þrēdijaną (“to thread”), cf. also Icelandic þræða, Norwegian træ, Swedish träda. Derived from the noun tråd, Proto-Germanic *þrēduz (“thread”).
træde (imperative træd, infinitive at træde, present tense træder, past tense trådte, perfect tense har trådt)
trǣde