1) This was a feature of the open fireplace, a fire-dog, one of a pair with horizontal bars which supported burning logs.
Among the earliest spellings were ‘andyar’ and ‘aundyre’ but the implement was made of iron so the spelling ‘andiron’ was almost inevitable: 1310 pro ij aundirnes emptis ad cameram Prioris xvjs, Bolton Priory
1380 duo magna aundyrns pro aula cum forco ferreo
1481 j par de awndeirenes, Thornhill
1542 two Andeyrons, Bretton Hall.