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ASME Y14.38-2007 — Abbreviations and Acronyms for Use on Drawings and Related Documents
✍️ ASME Y14.38-2007, Abbreviations and Acronyms for Use on Drawings and Related Documents, was prepared by Subcommittee 38 (Abbreviations) of the Y14 Standards Committee, formed in May 1995, and was approved as an American National Standard on September 12, 2007; it was reaffirmed in 2013. The Standard is based on ASME Y1.1 (which was revised and redesignated as ASME Y14.38) and MIL-STD-12, making it the authoritative reference for abbreviations on engineering drawings and related technical documents. The main body contains both a “words and terms and their abbreviations” list and a “cross-reference list of abbreviations and their words and terms,” plus a table of elements and their symbols (Nonmandatory Appendix A) and a partial list of engineering societies and industrial associations (Nonmandatory Appendix B).
💡 The Standard allows the use of approved abbreviations in lieu of complete words or terms, and abbreviations defined by the Standard need not be additionally defined by the using drawing or document — this saves significant sheet space while keeping the meaning consistent across companies and industries.
1. Scope and Purpose 📌
Chapter 1 of the Standard states its scope and purpose:
- Scope: lists the abbreviations and acronyms used on engineering drawings and related documentation;
- Purpose: to allow the use of approved abbreviations in lieu of complete words or terminology; abbreviations defined by this Standard need not be additionally defined by the using drawing or related document;
- Exceptions: abbreviations defined or established in other standards (such as those for scientific terms and notations) are not included, except for those with widespread use and recognition — for example, AM for amplitude modulation and FM for frequency modulation;
- Abbreviations and letter symbols: abbreviations are conventional representations of words or names in a particular language and may differ between languages, while a symbol represents a quantity or a unit (not its name) and is therefore language-independent. Consequently, the use of letter symbols is preferred over abbreviations for unit or quantity terms.
⚠️ Key rule: abbreviations are never to be used whenever a mathematical operation sign is involved, such as the equality sign or the division sign — letter symbols must be used instead.
2. List Structure and How to Use the Lists 🔧
Chapter 5, “Words and Terms and Their Abbreviations,” provides the forward lookup (word to abbreviation); Chapter 6, “Cross-Reference List of Abbreviations and Their Words and Terms,” provides the reverse lookup (abbreviation to word). Key format conventions of the tables:
| Column | Content | Applicable Context |
|---|---|---|
| Drawings column | Abbreviation form for drawings/documents | Documents produced with upper-case characters |
| Text column | Abbreviation form for text | Documents produced with lower-case characters |
| Words and Terms column | Complete word or term | Primary key of the forward lookup |
| Abbreviations column | Abbreviation/acronym | Primary key of the reverse index |
Upper-case abbreviations shown in the “Text” column are a continuation of prior usage and are generally for major systems or are recognized as having widespread use. Users should select the abbreviation form from the column matching the character case of the document and keep it consistent throughout.
💡 Practice tip: use the appropriate column for the environment — the Drawings form for upper-case drawing sheets and the Text form for lower-case body text. Using the drawing-style upper-case abbreviation in body text is not necessarily wrong but harms typographic consistency.
3. Relationship with Related Standards 📚
The lineage and connections of this Standard are as follows:
- ASME Y1.1: the older abbreviation standard, revised and redesignated as Y14.38, bringing it into the Y14 engineering drawing series;
- MIL-STD-12: the military drafting abbreviation standard, an important source of this Standard;
- Other Y14 series standards: such as Y14.3 (views), Y14.5 (dimensioning and tolerancing), and Y14.2M (line conventions and lettering), which reference this Standard’s list when abbreviations are used in their content;
- Nonmandatory Appendix A: table of chemical elements and their symbols, used for material annotation;
- Nonmandatory Appendix B: partial list of engineering societies and industrial associations, used to identify organization abbreviations.
The 2007 revision incorporates the ASME Y14.38a-2002 addenda and comments received since the 1999 revision. No abbreviations or acronyms were eliminated; however, one abbreviation was changed: SME, formerly “standard military drawing,” is now “standard microcircuit drawing.”
🚨 Abbreviation ambiguity is a major enemy of engineering documents: the same abbreviation can mean different things in different industries. When referencing this Standard, verify its unique meaning within the Standard; if a word is not included, write the full term rather than inventing a private abbreviation that will mislead downstream users.
4. Engineering Practice Essentials 🛠️
- 🔍 Double-direction lookup: when drafting, look up the abbreviation from the word (Chapter 5); when reading, resolve an unknown abbreviation from the reverse list (Chapter 6) — the two directions eliminate misunderstanding.
- 📐 Match the character case: use the Drawings-column abbreviation on drawing sheets and the Text-column form in document body text.
- 🔢 Symbols first: for units and quantities, prefer letter symbols (e.g., mm, kg, N); abbreviations are for word-level substitution only.
- 📋 Material annotation: combine material designations with the element symbols of Nonmandatory Appendix A so material names are uniform and traceable.
- ♻️ Verify the edition: abbreviations change across revisions (e.g., the meaning of SME changed); always cite the current edition and verify definitions.
✅ Good abbreviation practice: use standard abbreviations on drawings, choose the form per character case in text, and supplement with a legend or terminology list where necessary — saving space without ambiguity.
5. Frequently Asked Questions ❓
❓ Q: What is the relationship between Y14.38 and ASME Y1.1?
A: ASME Y1.1 was revised and redesignated as ASME Y14.38, bringing it into the Y14 engineering drawing series; current references should therefore cite Y14.38, not the obsolete Y1.1.
A: ASME Y1.1 was revised and redesignated as ASME Y14.38, bringing it into the Y14 engineering drawing series; current references should therefore cite Y14.38, not the obsolete Y1.1.
❓ Q: What is the difference between an abbreviation and a letter symbol, and why are symbols preferred?
A: An abbreviation is a conventional short form of a word and varies by language; a letter symbol represents a quantity or unit and is language-independent (e.g., mm is universal). Thus letter symbols are used for units and quantities, abbreviations only for word-level substitution, and abbreviations are never used in mathematical expressions.
A: An abbreviation is a conventional short form of a word and varies by language; a letter symbol represents a quantity or unit and is language-independent (e.g., mm is universal). Thus letter symbols are used for units and quantities, abbreviations only for word-level substitution, and abbreviations are never used in mathematical expressions.
❓ Q: Why does the Standard have both “Drawings” and “Text” columns?
A: Drawings are usually produced with upper-case characters and document text with lower-case characters; the two columns give abbreviation forms suited to each character case so that abbreviations match the style of the document.
A: Drawings are usually produced with upper-case characters and document text with lower-case characters; the two columns give abbreviation forms suited to each character case so that abbreviations match the style of the document.
🔍 Q: What should I do if an abbreviation is not in the Standard?
A: Write the full term first; if an abbreviation is truly necessary, give the complete term at first use in the drawing or document with an “abbreviation defined” note, and consider submitting a revision proposal to the Y14 committee so it can be included in the next edition.
A: Write the full term first; if an abbreviation is truly necessary, give the complete term at first use in the drawing or document with an “abbreviation defined” note, and consider submitting a revision proposal to the Y14 committee so it can be included in the next edition.
