The term Broadway Sign is a reference to the iconic signs that are found in New York City's theater district. The solutions to the crossword for this term are NEON (4 letters), NEONS (5 letters), and SRO (3 letters). NEON refers to the type of lighting used in the signs, which is a type of gas-discharge lamp that produces light by passing electricity through a tube filled with NEON gas. NEONS is a plural form of the same word, referring to multiple NEON lights. SRO stands for Standing Room Only, which is a term used to describe a theater or venue that is completely full.