Pregnant is much, much more common, but they mean the same thing. I had never heard the word 'gravid' until now :) It is a 'technical' term for pregnant, so it would usually be used by doctors or scientists. Some other common ways of saying pregnant are: 'with child' 'carrying a child' 'expecting [a baby]' There are also lots of slang sayings, but these aren't very nice: 'up the duff' 'up the stick' 'to have a bun in the oven' [this one isn't so bad]

You will never have to use the word 'gravid' in normal everyday English. We would normally use it while talking about an animal or fish with a large belly due to pregnancy or about to spawn.

There is not difference in the meaning and almost not in the origin They both come from Latin passing, for "pregnant", through Old France. Perhaps it is the reason why "pregnant" is more used than "gravid" in Anglo-Saxon context. You should check a technical dictionary (medical) to have more information and confirmations (those online send them again to the word pregnant). Don't worry about making mistakes, be only sure about the linguistic and technical context :-) pregnant : http://www.etymonline.com/index.php?term=pregnant&allowed_in_frame=0 gravid : http://www.etymonline.com/index.php?allowed_in_frame=0&search=gravid&searchmode=none http://search.medicinenet.com/search/search_results/default.aspx?navState=6483&sourceType=all&query=gravid&Search=Search

A woman or female animal having a baby or babies developing inside the body example= he got his wife pregnant. A woman who is in her last stages of pregancy is an example of someone who would be described as gravid. it also indicates the number of times the mother has been pregnant,