Defender of mankind
Sandria is a rare feminine elaboration of Sandra, which itself is a short form of Alexandra. It ultimately derives from the Greek name Alexandros, combining 'alexein' (to defend) and 'aner' (man).
Less common today
Sandria isn't in the latest US Top 1000. It last peaked at #6,940 in 1990.
US births per 5-year period, 1990βpresent (SSA data).