The term 'Nest Piece' can be solved by the four-letter word 'TWIG'. A TWIG is a thin, flexible branch of a tree or shrub that is used in the construction of bird nests. Twigs are often used as the main structural component of a nest, providing support and stability for the eggs and young birds. Twigs are also used to line the inside of the nest, providing insulation and protection from the elements.