What distinguishes an LCT from an LCM?

What is the difference between a Landing Craft Tank and a Landing Craft Mechanized?

LCTs were larger, carried more weight, and were much more capable of travelling under their own power; LCMs generally required transport.

The acronyms can sound interchangeable because both types move vehicles from ship to shore. The practical distinction is scale and independence: an LCT carries a heavier tank load and can undertake longer passages, while an LCM normally depends on a parent ship for transport to the operating area.