DTI is the old short name for Britain’s Department of Trade and Industry — the government office that used to look after business, trade, and factories. It is former: the department has been split, renamed, and replaced more than once, so there is no “DTI” door in London today. You still meet the letters in older British news, company histories, and official papers, especially from the 1980s to the 2000s. It is British politics, not a science term, and not the name of a Taiwan government office. Formal, and a little dusty. Though actually, many modern abbreviations start with D for “digital”; this D is just Department.