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baro-

American  
especially before a vowel, bar-
  1. a combining form meaning “pressure,” used in the formation of compound words.

    barograph.


baro- British  

combining form

  1. indicating weight or pressure

    barometer

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of baro-

Combining form of Greek báros weight; akin to Sanskrit guru, Latin gravis, Gothic kaurus heavy