The word "stem" has several meanings in English, and I will explain them in a simple way for you.
Noun (in plants): The "stem" is the long, thin part of a plant that supports the leaves and flowers. It is usually green and grows upward from the ground. For example, in a rose, the stem is the part that holds the flowers above the leaves.
Noun (in skiing): In skiing, a "stem" refers to a turn made by pushing one ski outward while keeping the other ski parallel to it. This helps the skier control their direction.
Noun (in linguistics): The "stem" is the main part of a word after you remove any prefixes or suffixes. For example, in the word "unhappiness," the stem is "happy."
Noun (in vessels or aircraft): The "stem" can also refer to the front part of a boat or an aircraft.
Noun (in pipes): The "stem" is the long, narrow part of a tobacco pipe that connects the bowl (where the tobacco is placed) to the mouthpiece.
Verb: To "stem" can also mean to stop the flow of something, like liquid or blood.
Phrase: "Stem the tide" means to stop or slow down a large problem or issue.
The word "stem" can be used in different contexts, including plants, skiing, linguistics, and even in more figurative meanings.