Stem

Botanical stem

In botany a stem is the plant axis that bears leaves, buds and reproductive structures and connects the shoot system to the roots. Major functions include mechanical support, transport of water and dissolved minerals via xylem, distribution of sugars via phloem, and storage or photosynthesis in some species. Morphological features include nodes (points of leaf attachment), internodes, apical and axillary buds. Stems may be herbaceous or woody; woody stems undergo secondary growth and can form trunks and branches. Many stems are modified for specific roles: stolons and runners spread plants horizontally, rhizomes and tubers store reserves, tendrils assist climbing, and cladodes or phylloclades take over photosynthesis in some plants.

Linguistics

In morphology a stem is the form to which inflectional affixes attach. The stem may be identical to a root or include derivational material. For example, in English the stem of "runs" is "run", and in a derived word the stem may be larger than the root. Related computational tasks include stemming (algorithmically reducing words to a common stem) and lemmatization (reducing to a dictionary form), both used in search and natural language processing.

STEM education

The initialism STEM groups science, technology, engineering and mathematics as an educational and policy focus intended to strengthen problem-solving skills and prepare a technical workforce. Programs and curricula under this label emphasise hands-on learning, interdisciplinary project work and efforts to broaden participation; variants such as STEAM add arts or design to the grouping.

Music, audio and other uses

• In music notation a stem is the short vertical line attached to a note head that helps indicate rhythmic value and voice direction.
• In audio production "stems" are grouped submixes (for example, drums, bass, vocals) used for mixing, mastering or performance.
• Other senses include the stem of a ship (the forward framing member), structural components (stem walls) and the common verb "to stem" meaning to originate from or to stop the flow of something.

Across these senses the unifying idea is a central element or axis that supports, gives rise to, or serves as the basis for other components.