Truncated form of "simma down now"; used specifically
when trying to hold one's keep, defending
against someone. Synonymous with "hold!!" or "wait!!"
in Lord of the Rings movie part
everyone's preparing to hold the fortress, you can at one point hear a determined "hooold!!, hoooolddd!!! hooooooollllld!!!!!". Well the alternative to that is
"simma!!!, simmmmmmaa!!!!!, simmmmmmaaaaaaa!!!!!!"