Definition of palo fierro in English:

palo fierro

Pronunciation /ˌpaləʊ fɪˈɛrəʊ/

noun

(also palo de fierro)
US
  • Any of various trees of desert regions in south-western North America with very hard, tough wood, especially desert ironwood, Olneya tesota (family Fabaceae (Leguminosae)).

Origin

Mid 19th century; earliest use found in Mayne Reid (1818–1883), novelist and children's writer. From American Spanish palo fierro, literally ‘iron tree’, a name given to various trees or their wood from palo, specific sense of palo + fierro (Spanish hierro) iron (from classical Latin ferrum see ferro-).