According to _Muslim & Parsi Names_ by Maneka Gandhi and Ozair Husain
, there are _four_ different names from Arabic that might come out as "Alam":
'Alam meaning sign, token, or mark
A'lam (with macron over the second a) meaning "signs, tokens", etc.
'Alam (with macron over the first a) meaning "world, universe, time"
A'lam meaning "having more knowledge; learned"
Finally, _Digest of Muslim Names_ by Fatimah Suzanne Al Ja'fari includes a female name "Ahlam", with a dot under the "h" and macron over the second "a", meaning "dreams".