Lamb's Wail is a traditional Irish folk song, also known as 'The Lament of the Sheep'. It is believed to have originated in the early 19th century and is still popular today. The song is about a shepherd who is mourning the loss of his beloved sheep. The title of the song is derived from the sound of the shepherd's wailing, which is likened to the bleating of a lamb. The crossword solution for Lamb's Wail is BAA, which is the sound that a sheep makes.