Yes, there are smaller units of length than a yoctometer (ym). The yoctometer is one of the smallest length units currently recognized. It is equal to 10^-24 meters, which is an incredibly tiny scale.
Beyond the yoctometer, there are additional units of length that describe even smaller scales. Here are a few examples:
Zeptometer (zm): One zeptometer is equal to 10^-21 meters, which is 1,000 times larger than a yoctometer but still incredibly small.
Attometer (am): An attometer is equal to 10^-18 meters, which is again larger than a zeptometer but still on the scale of subatomic particles.
Femtometer (fm): A femtometer is equal to 10^-15 meters. It is larger than an attometer but still incredibly small, commonly used in the field of particle physics to describe the size of particles and atomic nuclei.
The scale continues with smaller units such as picometers, nanometers, angstroms, and beyond. Each of these units represents a progressively larger length scale but still describes the realm of atomic and subatomic particles.