In common parlance, a stem is any elongated, usually narrow, extension or supporting structure of an object. Examples are the stem of a smoking pipe, stem of a cut flower, stem of a wine glass, etc. Uses of the term specific to certain fields are as follow:

• In botany, a stem is the above ground axis of a vascular plant.
• On a bicycle, the stem connects the fork to the handlebars.
• In linguistics, a stem is the base part of the word including derivational affixes but not inflectional morphemes, i. e. the part of the word that remains unchanged through inflection.
• In music, a stem is part of the annotation used to write musical notes.
• In rock climbing, a stem is a move that involves two widely spaced holds.
• In shipbuilding a stem is the upright structural member or post at the bow, which is attached to the foremost part of a vessel's keel.
• In typography, a stem is the upright element of a letter or character. The letter 'i' has one stem, 'n' has two stems, and 'm' has three.