1.  argonaut(n = noun.person) - someone engaged in a dangerous but potentially rewarding adventure;
is a kind of adventurer, venturer

2.  argonaut(n = noun.person) - (Greek mythology) one of the heroes who sailed with Jason in search of the Golden Fleece;
is a kind of character, fictional character, fictitious character

3.  argonaut(n = noun.animal) argonauta argo, nautilus, paper nautilus - cephalopod mollusk of warm seas whose females have delicate papery spiral shells;
is a kind of octopod
is a member of argonauta, genus argonauta

1.  Any one of the legendary Greek heroes who sailed with Jason, in the Argo, in quest of the Golden Fleece. [1913 Webster]

2.  A cephalopod of the genus Argonauta. [1913 Webster]
"The “Argonauts of '49” were a strong, self-reliant, generous body of men." [Webster 1913 Suppl.]

3.  One of those who went to California in search of gold shortly after it was discovered there in 1848. Bret Harte. [1913 Webster]