Derivation of Maid, Maidli, Meydli
Yes, I was wrong I thought also "maid" means somehow "girl". However this is true only for the Alemannic words Maydli, Meydli or Meydschi were the meaning is effectively little girl (= magadīn). I have now learned that the sense of a word is in that context here not the relevant point, the genetic relationship is what really matters.
magaþ => maiden, meiden => maid (young women)
magaþ => magad => maget => Maidli, Maydli, Meydli, Meydschi (girl, young girl)
And by the way, the page for German word "Maid" could be regarding this aspect improved. https://en.wiktionary.org/wiki/Maid
The same is true also for the the High German word "Mädchen" (which is effectively derived from magadīn). Also this page could be in this aspect somewhat improved.
magadīn => magedin => Mädchen
Thanks and regards
Unless I'm really missing something, German Mädchen is not a descendant of Proto-West Germanic *magadīn. Rather, German Mädchen is from German Magd + diminutive suffix -chen. German Magd is descended from Proto-West Germanic *magaþ.
Also, English maid is not derived from maiden, but is instead descended from *magaþ, same as German Magd. Meanwhile, English maiden is descended from *magadīn. The etymology currently given in the maid entry appears to be incorrect.
Well, it seems that this overall topic is somewhat more complex than I thought. So according to the answer from Eiríkr Útlendi, the following Mädchen entry in magaþ is also incorrect.
It would be really great if someone with a linguistic background can check & correct the whole matter.
However, at least the following derivation should be correct:
Alemannic Maydli is from (old?) German Mayd + diminutive suffix -li. So, the Alemannic term Maydli is effectively descended from Proto-West Germanic *magaþ.