Sawdah
Yes. Sawdah bint Zam'ah is a real, historically attested Sahabiyah who became one of the wives of Prophet Muhammad; she is cited in classical sira and hadith literature.
Linguistically it derives from the Arabic root s-w-d meaning 'black' or 'dark'. As a personal name its significance in sources is primarily as an identifier of a noted early Muslim woman rather than a descriptive epithet.
No. Her personal name does not appear in the Quran; information about her comes from sira (biographies) and hadith collections.
Sawdah is uncommon today but does occur, especially among families preserving traditional or classical Arabic names across South Asia, including Sindhi and Bengali Muslim communities.
Regional variants include Sauda and Sawda; formal usage typically retains the classical form Sawdah.