The term 'HEROIC TV DOG' can be summarized by the crossword solution 'LASSIE'. LASSIE is a fictional character created by Eric Knight in a 1940 short story that was later adapted into a novel and then a movie. The character has been featured in various media, including television series, films, books, and comic books. LASSIE is a female Rough Collie dog who is heroic and loyal, often rescuing her human family from danger.