decare vs farthingdale

decare

noun
  • A unit of surface area equal to 10 ares (that is, 1,000 square metres, 0.10 hectares, or approximately 0.25 acres) 

farthingdale

noun
  • A unit of area equal to one quarter of an acre. 

How often have the words decare and farthingdale occurred in a corpus of books? (source: Google Ngram Viewer )