dissertation (n.)
1610s, "discussion, debate" (a sense now obsolete), from Late Latin dissertationem (nominative dissertatio) "discourse," noun of action from past-participle stem of Latin dissertare "debate, argue, examine, harangue," frequentative of disserere "discuss, examine," from dis- "apart" (see dis-) + serere "to join together, put in a row, arrange (words)," from PIE root *ser- (2) "to line up."
Sense of "formal, written treatise" is from 1650s. Meaning "research paper required as a final project for a Ph.D or other doctoral degree" is attested by 1877 in reference to continental universities; it was in use in the U.S. by 1890. Related: Dissertational. There is no regular verb to go with it: Dissert (1620s, from French disserter, from Latin dissertare) is obsolete, and dissertate (1766) is marked "Unusual" in OED.
Dictionary entries near dissertation
disseminate
dissemination
dissension
dissent
dissenter
dissertation
disservice
dissever
disseverance
dissidence
dissident