An oval sign attached to the back of a road vehicle to show the nationality of the vehicle.

(medicine) The extension of a blister to adjacent unblistered skin when pressure is put on the top of the bulla.

(medicine) A sign of cholecystitis, etc. identified by the patient experiencing pain when the gall bladder is obstructed on the right-hand side while he/she breathes out.

(oceanographics, nautical) A standardized measure of trough-to-crest wave height calculated for the needs of seafarers; exact mathematical definition has varied over time and currently it is defined as four times the standard deviation of the surface elevation.

A front sight component used to assist the aiming of a projectile weapon. It consists of a hollow cylinder with a threaded cap, which allows differently shaped interchangeable front sight elements to be used.

A hinged sight on a firearm, which can be raised or folded down.

The unilateral painless periorbital swelling associated with the acute stage of Chagas' disease.

(Britain) V sign (of contempt or insult)

plural of significant digit

A sign in chest radiography that represents a focus of oligemia seen distal to a pulmonary embolism.