| Term | Definition |
| pyrrhic victory | A victory won at too great a cost. |
| casus belli | An action or event that causes or is used to justify starting a war. |
| tribology | The study of interacting surfaces in relative motion and associated issues, such as friction, lubrication, and wear. |
| nonplus | To put at a loss for what to do, think, or say; perplex. |
| pedology | The study of soil: its formation, usage, classification, etc. |
| chiaroscuro | The treatment of light and shade in a work of art, especially to give an illusion of depth. |