A label like 18° Taurus may look like a rating. It is simply a way to mark a place on the zodiac circle.
Each sign covers 30 degrees
In Western astrology, the twelve signs divide the circle into equal parts. Each sign starts at 0° and ends just before 30°. So 18° Taurus means a position 18 degrees into the Taurus part of the circle.
Read the name and number together
If a chart shows Mercury at 18° Taurus, Mercury is the marked body, Taurus is its sign, and 18° is its position within that sign. The number helps you locate the mark more precisely. It is separate from the house number elsewhere on the chart.
A coordinate is not a score
A higher degree does not make a person stronger or more like that sign. You can start by finding the sign and return to the degree when you need a closer look. The number alone does not describe anyone's character or future.
A few common questions
Is 29° more powerful than 5°?
Not by itself. Degrees mark positions. Some traditions give certain degrees a separate symbolic meaning, but a larger number is not a strength score.
Sources & further reading
Astrology sources describe their own traditions and methods; they do not establish predictive accuracy. The writing exercises are original Lodestar editorial material.