Thingie is a slang term used to refer to an object whose name is unknown or forgotten. In crosswords, the terms 'GADGET' and 'WIDGET' are often used as synonyms for thingie. Both words have 6 letters and refer to a device or object that performs a specific task. GADGET is derived from the French word 'gachette, ' which means 'small tool, ' while WIDGET is derived from the Old English word 'widian, ' which means 'to contrive or devise.'