disquisition (n.) Look up disquisition at Dictionary.com
c.1600, "subject for investigation," also "systematic search," from Latin disquisitionem (nominative disquisitio) "an inquiry, investigation," noun of action from past participle stem of disquirere "inquire," from dis- "apart" (see dis-) + quaerere "seek, ask" (see query (v.)). Sense of "long speech" first recorded 1640s.