The spelling of the word "Magruder" can be explained using IPA phonetic transcription. The first syllable is pronounced as /məˈɡruː/ with a schwa sound, followed by a long "oo" sound and stress on the second syllable /dər/. The "g" is hard and pronounced as /ɡ/, while the "r" sound is made by the back of the tongue as in /r/. This name is common in America and has various possible meanings, including "son of the magistrate" or "rider of the horse."
There isn't an established etymology for the word "magruder". It doesn't appear to have a widely recognized origin or meaning. It is possible that it could be a surname or a specific name used in certain cultures, but without any additional context or information, it is difficult to determine its exact origin.