"Sketchpad" is a versatile term that refers to a writing surface used for quick sketches or doodles. A synonym for sketchpad is "notepad," which can refer to any pad of paper used for writing or drawing. Another synonym for sketchpad is "sketchbook," which typically refers to a bound book with blank pages specifically meant for drawing and sketching. "Drawing pad" and "doodle pad" are also synonyms for sketchpad. Additionally, "notebook," "journal," and "diary" can be used as synonyms when referring to a book used for writing and sketching. Regardless of the term used, these types of pads and books provide a space for freeform creativity and brainstorming.