'antitrust' originates from English, specifically the combining form 'anti-' and the noun 'trust', where 'anti-' meant 'against' and 'trust' meant 'a business combination or monopoly'.

'antitrust' emerged in the United States in the late 19th to early 20th century in response to powerful 'trusts' (large business combinations) and became commonly used in terms such as 'antitrust law'.

Initially, it meant 'against trusts (business monopolies)', but over time it evolved into its current meaning of 'relating to laws or policies that prevent or regulate monopolies and anti-competitive behavior'.