| Term | Type | Business Meaning |
| --- | --- | --- |
| config.properties | Resource | External runtime configuration file containing application settings, including the currency API credential. |
| API_KEY | Property key | The configured secret token used to authenticate against the Exchange Rate API. |
| logger | Technical term | Logging component that records operational failures for support and diagnostics. |
| Properties | Technical term | Java configuration container that stores key/value pairs loaded from a resource file. |
| InputStream | Technical term | Stream used to read the configuration file contents from the classpath. |
| classpath | Technical term | Runtime resource location mechanism used to package and load application configuration. |
| Exchange Rate API | Business term | External currency exchange-rate service that requires an API key for access. |
| CurrencyRateAPI | Class name | Utility class that builds the remote currency-rate endpoint and retrieves the authentication key. |
| getURL() | Method | Companion method that concatenates the API base URL with the returned API key to form the service endpoint. |
| I/O | Acronym | Input/Output — file or resource access operations that can fail due to missing or unreadable configuration. |
| CRUD | Acronym | Create, Read, Update, Delete — data operation classification used here to describe the read-only configuration lookup. |