Treadling is a term used to refer to the process of pressing the pedals on a weaving or sewing machine to produce a desired effect. However, there are several synonymic words that can be used in place of treadling. For example, "pedaling" is a synonym that's commonly used in weaving circles. Additionally, "footwork" and "pressing" can also be used as synonyms for treadling. Some other less common but still valid synonyms include "stepping," "squeezing," and "depressing." Ultimately, the choice of which synonym to use depends on the context and the preference of the user.