Terminology
Ecliptic
The ecliptic is the apparent path the Sun follows across the sky over the course of a year. The Moon and most of the planets stay close to this path
Why it matters
The ecliptic is the line the Sun traces across the sky each year; the zodiac is the 30-degree-wide band built around it, divided into twelve signs. Since the zodiac is measured along this path, every planetary position in a birth chart or daily forecast is referenced from it
Why You Should Care
The ecliptic is a real astronomical feature. Once you know about it, you begin to understand why the planets always seem to travel through the same part of the sky.