freeboard vs umbrella

freeboard

noun
  • The vertical distance between the waterline and the uppermost watertight deck of a vessel. 

  • The distance between a water level and the top of something that contains or restrains it (such as a dam). 

  • The distance between the top of sea ice and the water level. 

  • A type of skateboard which simulates the movement of a snowboard when used on a downhill coarse, allowing snowboarding techniques, which has an addition of two centerline casters that extend below the traditional skateboard wheels and bogies. 

umbrella

noun
  • A cloth-covered frame used for protection against rain or sun. 

  • Something that covers a wide range of concepts, purposes, groups, etc. 

  • The main body of a jellyfish, excluding the tentacles. 

  • Generally, anything that provides protection. 

  • An umbrella-shaped reflector with a white or silvery inner surface, used to diffuse a nearby light. 

verb
  • To move like a jellyfish. 

  • To cover or protect, as if by an umbrella. 

  • To form the dome shape of an open umbrella. 

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