Lettering in engineering drawing is the process of forming letters, numerals, and other characters in technical drawing. It is used to describe or provide detailed specifications for an object, and it is essential for the clarity and accuracy of engineering drawings. The following are some key points about lettering in engineering drawing:

• Styles: Engineering drawings use a Gothic sans-serif script, formed by a series of short strokes. Lower case letters are rare in most drawings of machines.

• Methods: Freehand lettering is done without the assistance of tools, while mechanical lettering is done using tools such as lettering guides, templates, or using a small mechanical pantograph referred to by the Keuffel and Esser trademark "Leroy".

• Height: The height of the capital letter is taken as the base of dimension, and the main requirement of lettering on engineering drawing is legibility, uniformity, ease, and rapidity in execution. All letters should be capital, except where lower case is required for clarity.

• Computer-Aided Design: Modern drawings are lettered with computer-aided design software.

• Importance: Lettering in engineering drawing is a standard and hence country-specific. It is about using the correct proportion of the dimensions of the letters and numerals on the drawing sheet when preparing an engineering drawing using technical drawing standards. It is a language of precision, a conduit of ideas, and a testament to the meticulous craftsmanship of engineers.

In summary, lettering in engineering drawing is the process of forming letters, numerals, and other characters in technical drawing, and it is essential for the clarity and accuracy of engineering drawings. It is done using freehand or mechanical methods, and the height of the capital letter is taken as the base of dimension. Modern drawings are lettered with computer-aided design software, and it is a language of precision that is country-specific.