The word 凑巧 is a compound formed by combining two meaningful characters: 凑 (còu), which conveys the idea of "gathering together" or "converging," and 巧 (qiǎo), which means "coincidental," "opportune," or "skillful." Together, they create a concept where separate elements or circumstances fortuitously come together at the right moment, hence the word's meaning of "by coincidence" or "fortunately." It functions as an adverb or adjective to describe an event that happens by a lucky or unexpected chance, illustrating a common Chinese word-formation process where semantic elements merge to express an abstract, nuanced idea.