The term "drum tower" is a specific architectural element that refers to a tall structure built to house drums that were traditionally used to mark time in ancient Chinese society. However, there are many other words and phrases that could be used to describe a similar structure. Some synonyms for drum tower might include "bell tower," "watchtower," "observation tower," "lighthouse," or simply "tower." Depending on the context, other terms like "fortress," "castle," or "stronghold" may also be appropriate when describing a structure designed to provide military defense or a prominent, commanding presence in a city or landscape. Ultimately, the choice of synonym will depend on the specific historical or cultural context in which the structure is being discussed, as well as the desired tone or emphasis of the writing.