disquisition (n.)

c. 1600, "subject for investigation" (a sense now obsolete), also "systematic search, formal inquiry into some problem or topic," 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 (n.)). Sense of "a long speech, a formal dissertation" first recorded 1640s. Related: Disquisitional.