undecimalis

Undecimalis is a Latin-derived adjective meaning belonging to eleven or elevenfold. In scientific and scholarly writing, it is sometimes used as a descriptive epithet in Latinized taxonomic names, though it does not denote any formal rank or category by itself.

From undecem, meaning eleven, and the adjectival suffix -alis (pertaining to).

In taxonomy and biology, when used, undecimalis is typically descriptive rather than formal. It may indicate features organized in elevens, such as eleven petals or eleven body segments, but its use is rare and not standardized.

In mathematics, computing, and nomenclature, undecimalis would be a hypothetical adjective describing base-11 concepts or notations. The base-11 numeral system is uncommon in standard usage, with digits 0–9 and an additional symbol for ten; undecimalis would describe properties of such systems rather than prescribing a method.

In culture and fiction, undecimalis is sometimes used as a coined term for elevenfold phenomena, technologies, or organizations. Because the term is not part of established scientific or mathematical practice, its meaning depends on context.