The word 跟踪 is formed by combining two characters that each contribute a key part of the concept's core action. The first character, 跟, literally means "heel" and by extension "to follow closely", capturing the physical act of pursuit. It is paired with 踪, which means "trace", "trail", or "footprint", emphasizing the object or evidence being followed. Together, they create a vivid, logical compound where one element denotes the action (follow) and the other specifies its target (the trail), seamlessly merging to convey the idea of tracking or shadowing someone by sticking to their traces.