We don't have synonyms for monogon yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are monodon, monogyn and monogen.
(n) :
(geometry) A one-dimensional object comprising one vertex and one (not necessarily straight) edge both of whose ends are that vertex.
(n) :
(geometry) A two-dimensional object comprising one vertex, one edge both of whose ends are that vertex, and one face filling in the hollow formed by that edge.
(n) :
(geometry) A one-dimensional object comprising one vertex and one (not necessarily straight) edge both of whose ends are that vertex.
(n) :
(geometry) A two-dimensional object comprising one vertex, one edge both of whose ends are that vertex, and one face filling in the hollow formed by that edge.