When it comes to measuring something, the term "is level" is often used to describe when an object or surface is sitting perfectly straight. However, there are a variety of synonyms that can be used to convey the same meaning. For example, you might use "plumb" to describe something that is hanging straight down or "true" to indicate that something is perfectly aligned. Other synonyms for "is level" include "even," "flat," "horizontal," "flush," and "parallel." Each of these words can be used to describe a surface or object that is sitting completely straight, without any bumps, dips, or deviations.