The crossword solution for the term 'BIRDBATH BIT' is ALGA, which is a four-letter word. ALGA is a type of organism that is found in aquatic environments and is classified as a protist. It is a simple, plant-like organism that can range in size from microscopic to macroscopic. Algae are important components of aquatic ecosystems, providing food and oxygen for other organisms. They are also used in various industries, such as food production, pharmaceuticals, and bioremediation.