Merriam-Webster's Word of the Day for November 2, 2006 is:
perseverate \per-SEV-uh-rayt\ verb
1 : to repeat or recur persistently
2 : to go back over previously covered ground
To ensure the accuracy of his or her data, the scientist necessarily perseverates, repeating each experiment many times and comparing the results.
Did you know?
Looking at "perseverate" and "perseveration," you may guess that the latter was formed by adding a suffix to the former, but that is not the case. "Perseveration" is actually the older term. It has been around since the 1600s, when it was used as a synonym of "perseverance" (which at one time was pronounced, like "perseverate" and "perseveration," with the stress on "sev," instead of on "ver"). In the early 1900s, psychologists adopted "perseveration" for the act of repeating a behavior over and over again. (For instance, continually repeating the same syllable or word might be called "verbal perseveration.") Shortly afterward, those scientists wanted a verb for such acts of repetition, so they changed the "-tion" of "perseveration" to "-ate" and "perseverate" was born.
*Indicates the sense illustrated in the example sentence.