Yes! It's in contrast to gimbaled systems. Putting the measuring instrument on a gimbal simplifies the math and often improves accuracy, but at the expense that you need this large moving object that needs more power.

Gyros on gimbals have other drawbacks, such as drifting and gimbal lock.

Just gimbal lock. Drifting happens to all of them.

But also the gimbal mechanisms, gimbal low response time, etc.

The ultimate example of this is the incredibly accurate and expensive and complicated floating Advanced Inertial Reference Sphere used on the Peacekeeper ICBM.

https://en.wikipedia.org/wiki/Advanced_Inertial_Reference_Sp...

Except that a gimbaled system, if enclosed in a single box/pod, can also be described as a strapdown system. The term speaks more to separate modularity than how the system functions internally.