At first 'rekko' (列侯 in kanji) was called 'tekko' (徹侯 in kanji) but tekko contained a kanji of 徹, which appeared in the personal name of the Emperor Wu of Han (Han dynasty) (Che Liu, 劉徹 in kanji), so 'tsuko' (通侯) was used instead and changed into 'rekko' (列侯) later.
列侯は初め徹侯と言っていたが、漢武帝(漢)（劉徹）の諱である徹にふれる為に通侯に改められ、その後列侯に変わった。