(linguistics, history) The Egyptian language as written and spoken during the Early Dynastic Period, before the time of the earliest attested complete sentences.

an arch constructed at an angle other than a right angle

(architecture) An arch built in the body of a wall to relieve the pressure, as over a door or window.

(anatomy) The position of a vertebra enclosing and protecting the heart and other viscera.

siderosis

(religion) A chief or major heresy.

(religion) Highly heretical; being or relating to arch-heresy.

plural of arch-heresy

A landmark in Central London which lends its name to the surrounding area.

An arch less than a semicircle.