from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. A poisonous protein extracted from the castor bean and used as a biochemical reagent.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A toxic protein extracted from the castor bean.

from The Century Dictionary and Cyclopedia

  • n. An albuminoid substance of poisonous character obtained in small quantity from the seeds of the castor-oil plant, Ricinus communis.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. a toxic protein extracted from castor beans; used as a chemical reagent; can be used as a bioweapon


from The American Heritage® Dictionary of the English Language, 4th Edition

From Latin ricinus, castor-oil plant.


  • I was listening to people just last night, and, really, they weren't able to articulate the name ricin, and listen to do a group of people trying to explain it to others, what ricin was.

    CNN Transcript Jan 8, 2003

  • I wonder whether the Chilcot inquiry Report, 29 January will require Tony Blair to answer a question or two about the so-called ricin plot.

    Letters: Chilcot should look at the ricin plot

  • Free for a few years, he was then imprisoned for 2½ years accused of involvement in the so-called ricin plot.

    Letters: No justice for Taleb

  • Tholen, 53, wouldn't say much more about Von Bergendorff or the discovery Thursday of several vials of ricin, which is deadly in minuscule amounts, at the man's extended-stay hotel room on Valley View Boulevard near Flamingo Road.

    Ricin Man Identified-- Home, Warehouse to be Searched

  • The CDC lists on its Web site that it takes 500 micrograms of ricin, which is about the size of a pinhead, to kill a person.

    Understanding Ricin

  • The first was that further testing did confirm that the white powdery substance found in this hotel room is ricin, which is extremely dangerous, extremely powerful.

    CNN Transcript Feb 29, 2008

  • As we told you a few moments ago, we're going to go live to Washington, D.C. and a press conference there where earlier today, this afternoon some mail found in the mailroom of the Senate majority leader tested positively in the initial test for the compound ricin, which is very dangerous stuff and deadly stuff.

    CNN Transcript Feb 2, 2004

  • RACKAUCKAS: Well, we just learned yesterday that -- from the Food and Drug -- from the Food and Drug Administration that the baby food was contaminated with this castor oil that contains ricin, which is a-- which is a poison.

    CNN Transcript Jul 29, 2004

  • Now, castor beans sound pretty innocuous, but when they're ground down, they can be made into a product called ricin (ph), which is a deadly bio warfare agent.

    CNN Transcript Dec 8, 2002

  • Freed from its protective hard coating, the inside of the castor bean could be ground into a substance known as ricin.

    Bitter Harvest


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  • Yes, but it's all natural.

    August 19, 2009

  • Less than a milligram will kill you whether it is ingested or inhaled. It damages the ribosomes that carry out protein synthesis in cells.

    August 18, 2009