Skull and crossbones (symbol)
This article needs additional citations for verification. (April 2015) (Learn how and when to remove this template message)
A skull and crossbones is a symbol consisting of a human skull and two long bones crossed together under or behind the skull. The design originates in the Late Middle Ages as a symbol of death and especially as a memento mori on tombstones.
History of the symbol
The symbol is an ancient one, becoming widespread with the medieval Danse Macabre symbolism. From at least the 12th century, it has been used for military flags or insignia and as a warning of the ferocity of the unit displaying it. It became associated with piracy from the 14th century onwards, possibly even earlier. By the 15th century, the symbol had developed into its familiar form.
The Knights Templar organisation, active from the 12th until their demise in 1307, adopted a skull-and-crossbones flag to identify ships belonging to their vast fleet.  The skull and crossbones as a pirate's flag could well predate the Knights Templar 
The symbol came to be used to mark the entrances of many graveyards, particularly Spanish cemeteries and also as an easily identifiable warning on poison and other dangerous liquid and powder containers since the 19th century. The skull and crossbones were also popular on crucifixes made in Northern Europe during the 18th and 19th century, worn on rosaries or as larger wall hangings in religious orders Memento Mori and symbolising Christ's victory over death. These crucifixes were also placed on coffins during a funeral and then later given to the deceased's family 
The skull and bones are often used in military insignia, e.g. in coats of arms of some military regiments.
Symbol for poison
In 1829, New York State required the labeling of all containers of poisonous substances. The skull and crossbones symbol appears to have been used for that purpose since the 1850s. Previously a variety of motifs had been used, including the Danish "+ + +" and drawings of skeletons.
In the 1870s poison manufacturers around the world began using bright cobalt bottles with a variety of raised bumps and designs (to enable easy recognition in the dark) to indicate poison, but by the 1880s the skull and cross bones had become ubiquitous, and the brightly coloured bottles lost their association.
As the skull-and-crossbones symbol has also entered popular culture in the context of piracy and is undoubtedly its most well known icon, and since cartoonish pirates have become popular characters with children, there have been concerns that the "poison" symbol might have the effect of attracting the curiosity of small children familiar with "pirates" as depicted as a toy or play theme. For this reason, in the United States there has been a proposal to replace the skull and crossbones by the "Mr. Yuk" symbol. However, Mr. Yuk and his graphic rendering are registered trademarks and service marks of his creator, the UPMC Children's Hospital of Pittsburgh, and the rendering itself is additionally protected by copyright. This means that the name and graphic image cannot be used without a license from the owner—unlike the Skull and crossbones, which is in the public domain.
An early 17th century "plague panel" from Augsburg.
|Wikimedia Commons has media related to Poison warning signs.|
- "Dictionary and Thesaurus | Merriam-Webster". Merriam-webster.com.
- "Skull and Crossbones Emoji". Emojipedia. Retrieved 19 November 2017.
- "Symbolism of the Skull and Crossbones - Otherwise Known as the Deaths Head". Bibliotecapleyades.net. Retrieved 19 November 2017.
- "History of the Skull & Crossbones Symbol Used in Poison Warning Signs and Labels". Mysafetysign.com. Retrieved 19 November 2017.
- "BLESSED IF I KNOW". Freepages.genealogy.rootsweb.ancestry.com. Retrieved 19 November 2017.
- Blair, Margot. "Rosary Workshop: Rosary - Museum Crucifixes Europe - (Early Latin American) Skulls". Rosaryworkshop.com. Retrieved 19 November 2017.
- Griffenhagen, George B.; Bogard, Mary (19 November 1999). "History of Drug Containers and Their Labels". Amer. Inst. History of Pharmacy. Retrieved 19 November 2017 – via Google Books.