We don't have synonyms for accessus yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are access, accesses and accessbus.
(n) :
(Christianity, historical) In electing a pope, a method by which cardinals could change their most recent vote to accede to another candidate in an attempt to reach the necessary two-thirds majority and end the conclave.
(n) :
(Christianity, historical) In electing a pope, a method by which cardinals could change their most recent vote to accede to another candidate in an attempt to reach the necessary two-thirds majority and end the conclave.