1610s, from Dutch Sennecas, collective name for the Iroquois tribes of what became upper New York, of uncertain origin, perhaps from a Mahican name for the Oneida or their village. Earlier sinnekens, senakees; form probably influenced by the name of the ancient Roman philosopher.
send
sended
sender
send-off
send-up
Seneca
Senegal
senescence
senescent
seneschal
senicide