Variant of Rosalind, from Latin 'rosa linda' meaning beautiful rose, used by Shakespeare.
Rosalin is a graceful variant of Rosalind, a name whose roots stretch back to the Germanic tribes of early medieval Europe. It combines the elements "hros" (horse) and "lind" (soft, tender), though over centuries the romance of the Latin "rosa" (rose) colonized its popular perception, giving it a floral warmth its original bearers never intended. The name traveled through Norman French into English, where it took root during the Middle Ages as a mark of courtly refinement.
Shakespeare immortalized the closely related forms in two plays: Rosalind in As You Like It — the witty, cross-dressing heroine who orchestrates her own love story in the Forest of Arden — and Rosaline in Romeo and Juliet, the unattainable beauty Romeo pines for before Juliet supplants her. These literary echoes gave the name an aura of intelligence and romantic magnetism that has persisted for four centuries. Edmund Spenser also used the name for a beloved pastoral figure in The Shepheardes Calender, cementing its Renaissance credentials.
Rosalin specifically, with its unfussier ending, has always occupied a quieter register than the full Rosalind — more intimate, less theatrical. It enjoyed modest use through the Victorian era, when rose-derived names flourished, then retreated into rarity through the twentieth century. Today it reads as a discoverer's find: historically grounded, softly botanical, and carrying just enough literary shadow to reward those who recognize it.