Opca

OPCA is an initialism used in different fields to denote different ideas or organizations. In some discussions, it is used to refer to Out-of-Place Cultural Artifacts, items said to be found in contexts that do not fit established historical timelines.

In archaeology and related disciplines, OPCA is tied to the broader concept of out-of-place artifacts (OOPArts). Proponents claim such items challenge conventional chronology, while mainstream scholars emphasize rigorous dating, provenience, and contextual analysis, often classifying OPCA claims as misinterpretation, hoax, or error. The topic is a common feature in debates surrounding fringe or pseudoarchaeology.

Because OPCA is not a single, standardized term, it can also stand for various organizations, programs, or associations in different places. Without additional context, the intended meaning remains ambiguous.

This article uses OPCA primarily to refer to Out-of-Place Cultural Artifacts; readers should consult field-specific sources to determine which meaning is intended in a given instance.