and·i·ron 
(ăndī′ərn)
(ăndī′ərn)n.
One of a pair of metal supports used for holding up logs in a fireplace. Also called dog; also called regionally dog iron, firedog.
[Middle English aundiren, alteration (influenced by Middle English iren, iron) of Old French andier, probably from Gaulish *anderos, young bull (andirons often being decorated with ornaments shaped like the heads of animals); akin to Welsh anner, heifer.]
Our Living Language A number of words that formerly were limited to one region of the United States are now used throughout the country. Andiron was once Northern, contrasting with Southern dog iron and firedog. The Southern terms remain limited to that region, but andiron is now everywhere. Other formerly Northern words that have become national include faucet, contrasting with Southern spigot and frying pan, contrasting with Midland and Upper Southern skillet. Southern words that are now used nationwide include feisty and gutters.
andiron