c.1600, from Latin dissectus, past participle of dissecare "to cut to pieces" (see dissection). Or perhaps a back-formation from dissection. Related: Dissected; dissecting.
dissect dis·sect (dĭ-sěkt', dī-, dī'sěkt')
v. dis·sect·ed, dis·sect·ing, dis·sects
To cut apart or separate tissue, especially for anatomical study.
In surgery, to separate different anatomical structures along natural lines by dividing the connective tissue framework.