Wellman, of Anglo-Saxon origin, means 'well-known man'. It's derived from the Old English personal name Wælmunda and was popular among the Normans during the medieval period.
"The name Wellman experienced peaks in popularity during the years 1917 and 1926 with nine and seven births respectively. There was a gap of five years between the most recent recorded birth year of 1929 and the previous one in 1923, suggesting a possible decline in usage during that period."