astrologia
Elements
Fire, Earth, Air and Water group the signs into four symbolic families. Each contains three signs in the usual Western classification.
How it is defined
They are neither chemical components nor medical categories. An element combines with a modality: Aries, Leo and Sagittarius share fire but have different modalities.
How to read it
Symbols work in combination: a sign modifies a function and belongs to an element and modality. That combination provides more context than an isolated label.
A concrete example
When counting elements, specify whether you include only Sun and Moon or also ascendant and planets. Changing the factors changes the count and its possible interpretation.
Explore further
Compare Sun, Moon and ascendant within one chart. Identify which factor you are reading before applying a general description to your own situation.