expanse

 
Pronunciation: /ɪkˈspans, ɛk-/

noun

  • a wide continuous area of something: the green expanse of the forest
  • the distance to which something expands or can be expanded: the moth has a wing expanse of 20 to 24 mm

Origin:

mid 17th century: from modern Latin expansum 'something expanded', neuter past participle of expandere (see expand)