The Latin word is perpendiculum (or the adjective pendulus from which the neuter noun pendulum was later derived long after the days of Classical Latin), so "pendula" cannot be a correct original Latin form. At best it is an invented plural from the seventeenth century, pretending to be a Latin form. Dbfirs 21:57, 27 May 2009 (UTC)
Well, it seems actually, pendulum IS derived from pendulus, from which the neuter noun pendulum was derived. Thus, pendula is the correct plural form of pendulum. In this light, the above argument seems to contradict itself. Moreover, how exactly does pendulum derive from perpendiculum?
Also, referring to the entry, why is then "pendula" a hypercorrect form? --220.127.116.11 00:18, 24 January 2010 (UTC)