What is Stem ?
Stem is (noun) 1. the tall thin part of a plant which holds a leaf, a flower or a fruit Trim the stems before you put the flowers in the vase. Synonym stalk 2. the main stalk of a plant or tree A shrub with ivy growing up the stem. 3. a part of a wine glass like a col- umn Wine glasses with coloured stems. 4. the basic part of a word to which endings or prefixes are added 5. from stem to stern from the front of a boat to the back The boat was packed from stem to stern with tourists.(verb) to try to prevent something flowing or spreading First, try to stem the flow of blood. The police are trying to stem the rising tide of crime. (NOTE: stemming – stemmed)
source: Easier English, Student Dictionary Upper Intermediate Level