diaphragm vs overlay

diaphragm

noun
  • A contraceptive device consisting of a flexible cup, used to cover the cervix during intercourse. 

  • In a speaker, the thin, semi-rigid membrane which vibrates to produce sound. 

  • A thin opaque structure with a central aperture, used to limit the passage of light into a camera or similar device. 

  • Any of various membranes or sheets of muscle or ligament which separate one cavity from another. 

  • A floor slab, metal wall panel, roof panel or the like, having a sufficiently large in-plane shear stiffness and sufficient strength to transmit horizontal forces to resisting systems. 

  • A flexible membrane separating two chambers and fixed around its periphery that distends into one or other chamber as the difference in the pressure in the chambers varies. 

  • In mammals, a sheet of muscle separating the thorax from the abdomen, contracted and relaxed in respiration to draw air into and expel air from the lungs; also called thoracic diaphragm. 

  • A permeable or semipermeable membrane. 

verb
  • To reduce lens aperture using an optical diaphragm. 

  • To act as a diaphragm, for example by vibrating. 

overlay

noun
  • A covering over something else. 

  • A block of program code that is loaded over something previously loaded, so as to replace the functionality. 

  • A decal attached to a computer keyboard to relabel the keys. 

  • A pop-up covering an existing part of the display. 

  • A horse going off at higher odds than it appears to warrant, based on its past performances. 

  • A piece of paper pasted upon the tympan sheet to improve the impression by making it stronger at a particular place. 

  • A cravat. 

  • Odds which are set higher than expected or warranted. Favorable odds. 

verb
  • To lay, spread, or apply something over or across; cover. 

  • To put an overlay on. 

  • simple past tense of overlie 

  • To overwhelm; to press excessively upon. 

  • To bet too much money on. 

How often have the words diaphragm and overlay occurred in a corpus of books? (source: Google Ngram Viewer )