curvature
noun /ˈkɜːvətʃə(r)/
  /ˈkɜːrvətʃər/
[uncountable, countable] (specialist)- the state of being curved; the amount that something is curved- the curvature of the earth
- curvature of the spine
- The screen is made of stretched vinyl and has a slight curvature.
 Word Originlate Middle English: via Old French from Latin curvatura, from curvare ‘to bend’, from curvus ‘bent’.