To a smaller degree

Words referring to a smaller degree.

• What words indicate that something is becoming smaller in degree?
  decline decrease diminish drop dwindle fall plummet slide tumble
• What words refer to the amount by which something became smaller?
  decline (n) decrease fall reduction tumble
• What words refer to causing something to become smaller in degree?
  decrease lower reduce
• What words indicate that something is smaller than another thing in degree?
  less than lower