The french word "dit" could be translated as "said to be" or "known to be" or "known as" but it is realy a nick name or a second family name normally associated with a handicap Ex: "dit" Legros would mean the big/large/fat one. etc. It could also identifiy the trade parcticed by a person or the geographic description of the place of residence of the person.
I'm prsently doing some research on the DEVOST family origin. I could keep you up to date if you are interested to retrace YVONNE DEVOST.