The etymology of the name is at present contested. Robert S. P. Beekes has suggested a Pre-Greek origin. Others connect the name to σειρά (seirá "rope, cord") and εἴρω (eírō "to tie, join, fasten"), resulting in the meaning "binder, entangler", i. e. one who binds or entangles through magic song. This could be connected to the famous scene of Odysseus being bound to the mast of his ship, in order to resist their song.
Sirens were believed to combine women and birds in various ways. In early Greek art, Sirens were represented as birds with large women's heads, bird feathers and scaly feet. Later, they were represented as female figures with the legs of birds, with or without wings, playing a variety of musical instruments, especially harps. The tenth-century Byzantine encyclopedia Suda says that from their chests up, Sirens had the form of sparrows, and below they were women or, alternatively, that they were little birds with women's faces. Birds were chosen because of their beautiful voices. Later Sirens were sometimes depicted as beautiful women, whose bodies, not only their voices, are seductive.
The first-century Roman historian Pliny the Elder discounted Sirens as pure fable, "although Dinon, the father of Clearchus, a celebrated writer, asserts that they exist in India, and that they charm men by their song, and, having first lulled them to sleep, tear them to pieces." In his notebooks, Leonardo da Vinci wrote of the Siren, "The siren sings so sweetly that she lulls the mariners to sleep; then she climbs upon the ships and kills the sleeping mariners."
In 1917, Franz Kafka wrote in The Silence of the Sirens, "Now the Sirens have a still more fatal weapon than their song, namely their silence. And though admittedly such a thing never happened, it is still conceivable that someone might possibly have escaped from their singing; but from their silence certainly never."