The word "碑碣" is formed by combining the characters "碑" and "碣", both of which individually refer to stone tablets or monuments. "碑" specifically denotes a flat, inscribed stone slab often used for commemorative purposes, while "碣" refers to a taller, upright stone marker with similar functions. Together, they create a compound term that broadly encompasses various types of inscribed stone tablets, highlighting their shared material and purpose in recording text or marking sites.