sinistr(o)-

Left; the left side; left-handed.

Latin sinister, left.

Some examples: sinistral, of or on the left side or the left hand; the associated abstract noun sinistrality often refers specifically to left-handedness; sinistrorse (Latin sinistrorsus, from vertere, to turn), turned or spiralling upwards towards the left like a left-hand thread, or a spiral stair, or a plant curling anticlockwise around a support. The adjective sinister, suggestive of impending evil or harm, comes from the idea that something left-handed is inauspicious or unlucky (in heraldry it literally means ‘on the left-hand side’). See also dextro‑.