Anachronism and solecism are occasionally used interchangeably to mean something that does not properly belong to the setting or background in which it is placed and that is incongruous with it.
More specifically, anachronism implies a mistake in associating things which do not belong to the same time or age.
- an automobile in a story of American Civil War times would be an anachronism
- an eighteenth-century Chippendale chair is an anachronism in a seventeenth-century Jacobean room
When applied to something that does exist at the time under consideration, anachronism implies that the thing is behind the times or antiquated and useless.
- born a thousand years . . . too late and an anachronism in this culminating century of civilization
—London
Solecism, on the other hand, implies lack of concord or consonance through an association of things that does not accord with some standard (as of decency, propriety, or logic). One who in affectation introduces foreign words into English speech commits a solecism in language.
- I feel certain that a solecism of this kind—the introduction into a particular rite of features not sanctioned by the texts—would have seemed a shocking thing to . . . so accurate a scholar
—L. P. Smith - it is a solecism in Belize to describe people by their color . . . the colony prides itself… on absolute freedom from any taint of racial prejudice
—Norman Lewis