Pollywog is a term used to describe the larval stage of a frog or toad. It is also known as a TADPOLE, which is the seven letter solution to the crossword. The term 'pollywog' is derived from the Middle English word 'polwygle', which means 'head-wiggler'. The pollywog is an aquatic creature that has a long tail and a head with eyes and a mouth. It swims by wiggling its tail and uses its mouth to feed on algae and other small organisms.