In Italian arithmetics from the last quarter of the fifteenth century the words bilione or duilione, trilione, quadrilione or quattrilione, quintilione, cinquilione, or quinquilione, sestione or sestilione, settilione, ottilione, noeilione and decilione occur as common abbreviations of due volte millioni, tre volte millione, etc. In other countries these words came into use much later, although one French writer, Nicolas Chuquet, mentions them as early as 1484, in a book not printed until 1881. The Italians had, besides, another system of numeration, proceeding by powers of a thousand. The French, who like other northern peoples, took most if not all their knowledge of modern or Arabic arithmetic from the Italians, early confounded the two systems of Italian numeration, counting in powers of a thousand, but adopting the names which properly belong to powers of a million.
For a time in Britain gillion (1961), based on giga-, was tried as "a thousand million" to avoid ambiguity.前缀bi-, 二。million, 百万。字面意思是万亿，现通常指十亿。
该词的英语词源请访问趣词词源英文版：billion 词源，billion 含义。
词根词缀： bi-两,二 + million → billion
英语单词billion来自法语，由bi-（两个）和million（百万）构成，因此本意是million million（万亿）。进入英语都保留了“万亿”的本意。但后来，也许是因为“万亿”这个单位太大，曾经有段时间，billion在法语中的含义从“万亿”变成了“十亿”。美国人也采用了法国人的做法，也许是因为在美国独立战争中美国人和法国人并肩和英国人作战的缘故。法国从1948年开始将billion的含义恢复到它的本意“万亿”，但美国依然坚持用billion来表示“十亿”而非“万亿”。就这样，同一个英语单词billion，在美国和英国的含义相差了整整一千倍。不过，为了避免混淆，英国曾经在1961年用表示“十亿”的词根giga-创造了新单词gillion，表示“十亿”。不过，随着美国文化影响力日益增大，越来越多的英国人也开始采用美国人的做法，用billion来表示“十亿”而非“万亿”。
billion：['bɪljən] n.十亿adj.十亿的