The word 固定 is formed by combining two characters, each contributing its inherent meaning to create a new, composite idea. The first character, 固, carries the core meaning of "solid", "firm", or "hard". The second character, 定, means "to settle", "to decide", or "to be stable". When joined, the concept flows naturally from "making firm and settled" to the combined meaning of "to fix in place", "to fasten", or "immovable", representing the action or state of becoming securely established and unchanging.