siusay noun English. The immature stage of the nanga rattan palm (Used as a component for anointing a bride and groom, to ward off evil.) Example sentence: Subanen. Bena' metubus, sumbeli'en dayun su manuk, petanda' dun su selumaya', siusay, selimbangun, tubu'tubu', bu' su pideng nu manuk. English. Then the chicken is killed, and the selumaya', siusay, selimbangun, tubu'tubu' herbs and feathers are mixed with the blood. Generic. uay