A V-shaped pattern; used in architecture, and as an insignia of military or police rank, on the sleeve. / (heraldry) A wide inverted V placed on a shield.

(intransitive) To duck under a surface and cover one's face with one's hands, as a means to protect oneself from flying debris etc.

Synonym of extenuating circumstance

(chemistry, dated) An acid prepared by dissolving mellonuret of potassium in boiling water, and adding hydrochloric acid, sulphuric acid, or nitric acid.