verb

The students hypothecated that plants under observation would have different reactions when exposed to artificial light versus natural light.

“‘Can someone hypothecate where Scotland and Yorkshire would rank in the medal table?’ says Marie Meyer.” — From the (London) Guardian’s Olympics 2012 live blog, August 5, 2012

“Hypothecate” is a controversial word. It has existed as a synonym of “hypothesize” since 1906, showing up primarily in scientific and linguistic sources, but usage commentators have long criticized it. It is sometimes perceived as a mistaken use of another “hypothecate,” one meaning “to pledge as security without title or possession.” Both “hypothecate” homographs—and “hypothesize” too—derive ultimately from the Greek “hypotithenai” (“to put under,” “to suppose,” or “to deposit as a pledge”), but each entered English by a different route. The hypothesizing “hypothecate” is a legitimate (albeit uncommon) word in its own right, not a misuse of its homograph. If you want to avoid the controversy altogether, however, you can stick with the more common “hypothesize.”

From Merriam-Webster Online at www.Merriam-Webster.com.