We don't have synonyms for syconium yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are conium, synovium and syngonium.
(n) :
(botany) A collective fleshy fruit, in which the ovaries are hidden within a hollow receptacle, as in the fig; a hollow ball with a stalk at one end and an opening (ostiole) at the other, with flowers or fruits on the inside
(n) :
(botany) A collective fleshy fruit, in which the ovaries are hidden within a hollow receptacle, as in the fig; a hollow ball with a stalk at one end and an opening (ostiole) at the other, with flowers or fruits on the inside