Liber

Liber is a Latin term with several distinct senses and uses across language, botany, and religion.

In classical Latin, liber is a noun meaning "book" (plural libri). As an adjective, liber can mean "free" or "unconstrained" (with related forms liber, libera, liberum). The same root yields many English words such as liberal, liberty, and liberate.

In botany, liber refers to the inner bark of a woody plant—the phloem and its associated tissues. It lies outside the xylem and is produced by the vascular cambium. In older botanical literature, "liber" is the term used for this tissue; modern texts more often call it phloem. Bast fibers used for rope and textile production (such as flax, hemp, and jute) are derived from cells in the liber.

In Roman religion, Liber is the god of fertility, wine, and freedom, often paired with Libera. He is commonly identified with Dionysus (Bacchus) in Greek tradition. His festival Liberalia was celebrated on March 17.

In manuscript and scholarly Latin, liber can also denote a book or a major division of a work, with sections labelled Liber I, Liber II, and so on.

Researchers and translators sometimes note the word's context to distinguish between the "book" sense, the "free" sense, and the botanical sense, as the different uses of a single Latin form.