What does 'numiform' mean?

The term 'numiform' originates from the Latin word 'nummus,' which means coin, and the suffix '-form,' meaning shaped like or resembling. Therefore, 'numiform' refers specifically to something that is arranged or shaped like a stack of coins. This definition connects directly to the concept of a specific arrangement or form that mimics that of coins stacked together.

The other choices do not align with the meaning of 'numiform'; they pertain to different concepts entirely. For example, the term that involves the brain relates to neurology and the study of the nervous system, while the definition associated with being harmful refers to toxicity or danger. Lastly, dental treatment pertains to oral health and medical procedures specific to teeth and gums, which is unrelated to the shape or arrangement of coins.

In summary, 'numiform' accurately denotes an arrangement akin to coins, which is why option A is the correct interpretation of the term.