Short form of Alexandra, from Greek meaning "defender of mankind."
Sandra began as a shortened form, but it long ago grew into a full name with its own identity. It is most often derived from Alexandra, the feminine form of Alexander, from Greek elements meaning "to defend" and "man" or "humanity." In some cases Sandra also comes from Cassandra, the Trojan prophetess of Greek myth.
That gives the name two overlapping classical backgrounds: one protective and heroic, the other prophetic and tragic. Its tidy, two-syllable shape helped it travel easily across languages, from Greek roots into Italian, Germanic, Slavic, and English-speaking cultures. The name rose to major popularity in the twentieth century, especially from the 1940s through the 1970s, when it came to sound modern, polished, and approachable.
S. Supreme Court, while actress Sandra Bullock gave it warmth and mainstream familiarity in film. In Europe, forms such as Sandrine, Sandrina, and Alessandra show how readily the name adapts while keeping its recognizable core.
Because of its popularity in the mid-century decades, Sandra now carries a slightly vintage aura, though not an antique one. It is a name many people associate with competence, steadiness, and understated grace. Literary and mythic associations remain in the background, but Sandra's real story is one of evolution: a clipped nickname that became a complete classic, strong enough to stand on its own.