HONG KONG — Thousands of people marched in Hong Kong on Sunday to protest an expected decision by the Chinese government that would effectively block two newly elected politicians from taking their seats in the semiautonomous territory’s legislature.

The decision, issued the next day, came after the prospective lawmakers, Sixtus Leung, 30, and Yau Wai-ching, 25, made controversial remarks last month during an oath-taking ceremony in Hong Kong’s Legislative Council. Rather than say “China” in their oaths, they said “Chee-na,” a term that many find offensive, associating it with its use by Japan during its occupation of China during World War II. Ms. Yau also added an expletive to her oath.

Relations between the Chinese mainland and Hong Kong, a former British colony of 7.3 million, were already frayed by pro-democracy demonstrations that erupted in 2014 in response to the Chinese government’s rejection of calls for free elections in the territory. The remarks by the two politicians, who have argued that Hong Kong should be independent from China, were widely seen as acts of defiance — and catalysts for a renewed political crisis.

Where does the term ‘Chee-na’ come from?

Aoki Masaru, a Japanese Sinologist, argued that it originated in early Sanskrit transcriptions of Qin, the name of the dynasty that unified China more than 2,000 years ago, according to a 2012 essay by the historian Joshua A. Fogel. Qin, pronounced “chin,” may have contributed to the country’s name in many Western languages. With the spread of Buddhism from India, and the translation of scriptures into Chinese, the word entered China and then Japan. Professor Fogel, who teaches at York University in Toronto, wrote that the Japanese used the name Chee-na for centuries, but especially from the 19th century through World War II.