The web page (at http://members.aol.com/jeff570/mathword.html) quotes Morris
Kline in Mathematical Thought From Ancient to Modern Times, page 255, as
attributing the coinage of the term to Wallis in Opera Mathematica vol. I in
1695. However Drazin has found the phrase "continue fracta" in Arithmetica
Infinitorum Prop. CXCI. So perhaps Wallis coined the term in 1655.
However, Drazin is interested in knowing who coined the term in English or
who translated it into English. I can forward any posts to him, but his
address is:
Philip G Drazin
P.Drazin@bristol.ac.uk