means A young unmarried woman or girl, or by extension something done or used for the very first time (as in a maiden voyage or maiden speech).

from From Old English 'mægden,' a diminutive form tied to 'mægð' meaning a maid or virgin, and a cousin of German 'Mädchen.' The Old English diminutive ending is the same little '-en' that shrinks a maid into a maiden. The 'first time' sense — maiden voyage, maiden over, maiden speech — grew from the older notion of something untouched and unused, much like the word's original sense of virginity.