Transferred use of the surname, which is an occupational name for someone who trimmed the nap of woollen cloth after it had been woven, from Old English scēara ‘shears’ + mann ‘man’. In the United States it is sometimes bestowed in honour of the Civil War general William Tecumseh Sherman (1820–71).
Irish: Anglicized form of Gaelic Ó Briain ‘descendant of Brian’, a personal name probably based on the element bre- ‘hill’, with the transferred sense ‘eminence’, i.e. ‘exalted one’. See also Bryan. In Ireland there has also been some confusion with O’Byrne (see Byrne).