means To make a harsh, high-pitched, piercing sound — or the sound itself.

from Screech is an imitative word — it sounds like what it means. It grew out of an earlier English form, 'scritch,' itself echoing the shrill cry it described; both are cousins to a family of 'scr-' words (screak, scream, shriek) that English keeps around for things that hurt the ear. The reshaped 'screech' had largely taken over by around the 16th century.