Definition of "diaphragm" []

• Anatomy A muscular membranous partition separating the abdominal and thoracic cavities and functioning in respiration. Also called midriff. (noun)
• A membranous part that divides or separates. (noun)
• A thin disk, especially in a microphone or telephone receiver, that vibrates in response to sound waves to produce electric signals, or that vibrates in response to electric signals to produce sound waves. (noun)
• A contraceptive device consisting of a thin flexible disk, usually made of rubber, that is designed to cover the uterine cervix to prevent the entry of sperm during sexual intercourse. (noun)
• A disk having a fixed or variable opening used to restrict the amount of light traversing a lens or optical system. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "‡ The term diaphragm can also refer to a small flexible cap, usually made of rubber, that fits over the cervix and is used for contraception."
• "In Handbook for Scientific Photography (1977), Alfred A. Blaker wrote: As the substage diaphragm is closed, the depth of field increases (as when you close the diaphragm of your camera lens) ..."
• "Hopefully Elaine's diaphragm is still in good shape, although she may want to cut back a bit on unnecessary usage so it doesn't wear out before the new ones are available."