Look up royalist in Wiktionary, the free dictionary.
A royalist supports a particular monarch as head of state for a particular kingdom, or of a particular dynastic claim. In the abstract, this position is royalism. It is distinct from monarchism, which advocates a monarchical system of government, but not necessarily a particular monarch. Most often, the term royalist is applied to a supporter of a current regime or one that has been recently overthrown to form a republic.
In the United Kingdom today, the term is almost indistinguishable from "monarchist," because there are no significant rival claimants to the throne. Conversely, in 19th-century France, a royalist might be either a Legitimist, Bonapartist, or an Orléanist, all being monarchists.
Loyalists during the American Revolution were American colonists opposed to secession from the British Empire and who remained loyal to the British Crown. After the Revolution, many emigrated north to the remaining British territories in what is now modern Canada, calling themselves the United Empire Loyalists.