A tub refers to a large container or basin that is often used for bathing or washing oneself. In the context of "Rubber Duckie" singalong, it refers to a bathtub or a specific setting where people might gather to sing the popular children's song "Rubber Duckie."
Note: The provided meaning of the answer is for the latest New York Times crossword puzzle clue: Ice cream container. Explanations are generated by AI and may be inaccurate.