Stem

Stem is a term which is commonly used for the uninflected part of a word. A stem is a morphological constituent to which affixes may be attached or to which morphological operations may be applied.


 * "A stem is any morpheme or combination of morphemes to which an affix can be added." (Gleason 1955:59)

Example
If we take the plural form disagreements, the form disagreement is called the stem. In languages such as Ancient Greek, in which words belong to different declensional or conjugational classes (marked by a theme or extension), the stem includes these extensions. For example, Ancient Greek declension I nouns are formed by adding the vowel a to the root gÃ©phur+a- 'bridge', while declension II nouns are formed by adding the vowel o to the root hÃ­pp+o- 'horse'. The inflectional endings for case and number are added to these forms. Traditionally, the forms gÃ©phura- and hippo- are called stems, while gÃ©phur- and hipp- are called roots.

Links
Utrecht Lexicon of Linguistics

Other languages
German Stamm