halitosis這個自來自於拉丁文的halitus，這個字第一次出現是在1874年，意思是呼吸，不過比較強調呼氣的部分（breath, exhalation, steam, vapor）；它與拉丁文的 halare （意為呼吸，一樣是著重在呼氣的部分： to breathe, emit vapor）。而字尾 -osis 在第二十三課（一）學過，是與疾病有關的字尾。一樣跟呼吸有關有個字尾 -pnea，它是由希臘文的 pnoia來的，意思也是呼吸（breath)，在第二十五課（二）有學到。
The word "halitosis" was first appeared in 1874. Halitosis means "bad breath". The word is originated from Latin halitus, meaning breath, exhalation, steam, vapor. It is related to halare (to breath, emit vapor). There is a suffix "-pnea" also meaning breath and it is originated from Greek pnoia (breath). We learn that in Lesson 25-2.
According to Wikipedia, halitosis is the third most frequent reason for people to seek dental care, following tooth decay and gum disease. Because about 20% of the general population are reported to suffer from it to some degree, anything that claim to be able to reduce halitosis (chewing gum, breath mint) are quite popular.
Not all who think they have halitosis really have it. Significant percentages (5–72%) of people who suspect that they have halitosis have been reported not to have genuine halitosis when examined by professionals. Most of the occasion of halitosis (about 90%) is caused by bacteria present below the gumline and on the back of the tongue. The remaining 10% could be resulted from disorders in the nasal cavity, sinuses, throat, lungs, esophagus, stomach or elsewhere.
Online Etymology : halitosis.