When Hamilton uses the word factions in the Federalist papers who and what is he referring to?

In the Federalist Papers, particularly Federalist No. 10, Hamilton refers to factions as groups of individuals who gather together to promote their own interests, often at the expense of the common good. He is primarily concerned with political parties and special interest groups that can lead to division and conflict within society. Hamilton argues that a large republic can help mitigate the negative effects of factions by diluting their influence and encouraging a wider range of interests to coexist.