gadget vs labor-saving device

gadget

noun
  • Any consumer electronics product. 

  • Any device or machine, especially one whose name cannot be recalled. Often either clever or complicated. 

  • A sequence of machine code instructions crafted as part of an exploit that attempts to divert execution to a memory location chosen by the attacker. 

  • A technique for converting a part of one problem to an equivalent part of another problem. Used in constructing reductions. 

labor-saving device

How often have the words gadget and labor-saving device occurred in a corpus of books? (source: Google Ngram Viewer )