Definition of "blastocyst" [blas•to•cyst]

• The modified blastula that is characteristic of placental mammals. Also called blastodermic vesicle. (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.

• "Who gets to decide if a blastocyst is a child or not?"
• "I know that a fetus, embryo or blastocyst is not a baby … or a person, they just have the potential to become one."
• "Douglas, if you truly believe that a blastocyst is morally equivalent to a (let's say) four year old boy, then they are indeed butchering and murdering them, and an evil larger than the Nazi Holocaust is going on."