Definition of "fictious"

Man does vvith dangerous Curioſity / Theſe unfathom'd VVonders try: / VVith fancy'd Rules and Arbitrary Lavvs / Matter and Motion he reſtrains, / And ſtudy'd Lines and fictious Circles dravvs; […]

1688, Mat[thew] Prior, “On Exodus 3. 14. I Am that I Am. An Ode. […]”, in Poems on Several Occasions, 2nd edition, London: […] Jacob Tonson […], published 1709, stanza VI, page 4