singlefold

Singlefold is a term that appears in different disciplines with varying meanings, and there is no single, universally accepted definition. In many contexts it functions as a descriptive label rather than a formal concept, and its exact sense is best understood from the surrounding literature or usage.

In topology and geometry, the phrase is sometimes used informally to describe a covering map of degree one, known more precisely as a 1-fold or degree-one covering. For connected spaces, such a map is essentially a homeomorphism and does not introduce a new layer of structure. Because “singlefold” is not standard terminology in formal texts, most sources prefer the explicit label “1-fold covering.”

In manufacturing, packaging, and origami-inspired design, “singlefold” may denote a process or item produced by a single folding operation. Examples include singlefold envelopes or cards formed by one crease, or products marketed to emphasize simplicity, compact form, or ease of assembly.

In biochemistry and protein folding, some authors have used the term to describe folding behavior characterized by a single dominant conformation or a single cooperative transition, in contrast with multi-state folding. This usage is not standardized and should be interpreted within the context of the source material.

Because the term is not widely standardized, readers should consult the specific publication, product documentation, or field context to determine the intended meaning. It may also appear as a brand name or product label in commercial settings.

See also: one-fold, 1-fold covering, covering space, folding (origami).