Which symbol represents diameter in engineering drawings?

The symbol that represents diameter in engineering drawings is a circle with a diagonal line going uphill. This symbol, often depicted as "∅," is universally recognized in technical and engineering contexts to indicate the diameter of circular features, such as holes or pipes. The use of this symbol provides a clear and concise way to convey measurements related to the diameter, making it essential for clarity in manufacturing and construction documents.

The other symbols mentioned do not represent diameter. The square shape typically represents different types of features or can be indicative of a specific area, while the triangle shape is often used to denote angular measurements or other geometrical features. The wavy line is generally not used in traditional engineering drawings, as it may suggest a different kind of feature or action, such as indicating an oscillation or an irregular boundary. Understanding these symbols is crucial for interpreting engineering drawings accurately.