Short form of Alexander, from Greek 'alexandros' meaning 'defender of the people'.
Sander is Alexander stripped to its active core. The full name derives from the Greek Alexandros — a compound of alexein ('to defend') and aner/andros ('man'), producing the magnificent meaning 'defender of men.' In the Scandinavian and Low German worlds, the name was pruned to Sander centuries ago, not as a diminutive but as a standalone name with its own vigorous character, used by farmers and fishermen and merchants who had no need for Macedonian grandeur but plenty of use for a strong name that was quick to say.
In the Netherlands and northern Germany, Sander appears in records as early as the medieval period, and it remains a staple given name in Dutch, Norwegian, and Danish communities. The name gained broader international exposure partly through Sander Levin, the American politician, and partly through the general drift of Nordic and Dutch names into English-speaking fashion that accelerated in the early twenty-first century. Unlike the more common variant Alexander, Sander never accrued the weight of expectation that a name borne by a world-conqueror naturally accumulates.
The appeal of Sander today is its exactness. It is neither fashionable nor unfashionable — it predates both categories. Parents who choose it often want something rooted in a specific heritage, or simply a name that sounds confident without performing confidence. It has one job — to identify a person clearly — and it does that job without decoration.