The word "土司" is formed through a dual-path construction: historically, it is a semantic compound where "土" (tǔ, meaning 'local' or 'indigenous') combines with "司" (sī, meaning 'to administer' or 'office'), creating the term for "native chieftain" or "hereditary tribal ruler" in imperial China, denoting a system of local governance. Simultaneously, in modern usage, it functions as a phonetic loanword, where the sounds "tǔ sī" are borrowed to transliterate the English word "toast," referring to sliced bread. Thus, its formation represents both a meaningful historical compound and a modern homophonic adaptation.