調

It is a phono-semantic compound, formed from:

言 (“speech, words”) as the semantic element;

周 (“all around, comprehensive”) as the phonetic element.

In Korean usage, 조 (調) is extremely common in both everyday and technical vocabulary:

조절 (調節) – adjustment, regulation

조사 (調査) – investigation, inquiry

조화 (調和) – harmony, concord

가락/음조 (音調) – tone, melody

조율 (調律) – tuning, settlement

장조/단조 (長調/短調) – major/minor key in music

Thus, while historically tied to the idea of speech and order, 調 has developed into a core character for expressing adjustment, regulation, investigation, and musical harmony across East Asian languages.