pellucido

Pellucido is a masculine singular Italian adjective meaning transparent or clear. It is derived from the Latin pellucidus, formed from per- “through” and lucidus “bright.” The feminine form is pellucida and the plural forms are pellucidi (masculine) and pellucide (feminine).

In Latin, pellucidus appears in classical and later texts to describe things that are visibly clear or transparent, such as water, glass, or other materials through which light passes readily. The term is preserved in scientific and scholarly vocabulary through phrases like zona pellucida, literally “the transparent zone,” a glycoprotein layer surrounding oocytes in mammals and playing a key role in fertilization. The feminine form pellucida is used to agree with feminine nouns in Latin and in modern Italian.

In English and other languages, the root appears most commonly in the adjective pellucid, meaning easily understood or intelligible, and in the noun pellucidity, referring to transparency or clarity. In scientific contexts, pellucid describes substances that are easily seen through, such as pellucid water or pellucid glass. A well-known biomedical usage is pellucid marginal degeneration, a corneal thinning disorder named for its characteristic clear, thin peripheral cornea. The word thus spans general usage for visual transparency to specialized terms in biology and medicine.

Overall, pellucido and its related forms convey the sense of translucence and clarity, applied across languages, literature, and various scientific disciplines.