What is the difference between text adventures and interactive fiction?

The difference is mostly one of scope: 'interactive fiction' is the broad, modern umbrella term for any story you play through text and choices, while 'text adventure' usually refers to the older, parser-driven games where you type commands like 'go north' or 'take key'. Every text adventure is a form of interactive fiction, but interactive fiction also includes choice-based stories where you click options instead of typing, plus hybrids and experimental work. In casual use people treat the terms as near-synonyms, and that is fine. The practical distinction is input: 'text adventure' leans toward typed parser commands, 'interactive fiction' covers that plus click-based branching. You can play modern, choice-based examples in the browser on the play page.