The PIARC technical Dictionary of road terms, whose first edition was published in 1931, basically includes specific road terms. The two official languages of the Association being French and English, this Dictionary is a basic dictionary. It refers to terms and definitions used in France and in the United Kingdom. However, special terms used in Belgium, Switzerland and the United States are also mentioned.

This seventh edition is the outcome of an update of the sixth edition completed by the PIARC Commission on Terminology with contributions from the Technical Committees of the Association, each within its field of competence.

Terminology in any given field is subject to constant change. In preparing draft European and other international standards, several technical committees of the European Committee for Standardization (CEN) and the International Organization for Standardization (ISO) involved in fields relating to roads and road use make significant contributions to the establishment of road terminology. That is why it has seemed useful to include in the Dictionary a number of terms and definitions adopted by those technical committees and approved (for the definitions sometimes in an abridged or slightly amended form) by the relevant PIARC Technical Committees, while suffixing the additions with (CEN) or (ISO) to acknowledge their origin.

The Dictionary includes about 1,200 concepts; more than 350 of these concepts are explained, particularly each time that one of them does not have any equivalent in the other language.

The Dictionary proposes a logical nomenclature distributed in sixteen sections:

1. types of road
2. design and geometry
3. traffic
4. intersections
5. components of the road
6. drainage
7. auxiliary works and accessories
8. structure of the pavement
9. materials
10. construction
11. qualities, faults and tests
12. engineering structures
13. maintenance, winter maintenance and management
14. economics and finance
15. tunnels