An optical illusion in which a spoked wheel appears to rotate differently from its true rotation, sometimes caused by stroboscopic effects.

(biology) A hypothesis in evolutionary biology that explains selective altruism among individuals of a species, involving preferential treatment of individuals with certain characteristics.

A polar mirage caused by high refraction of sunlight between atmospheric thermoclines.

plural of Novaya Zemlya effect

(psychology) The tendency to more easily recognize members of one's own race.

(psychology) An effect observed in fighter aircraft pilots, where horizontal acceleration at more than 1 standard gravity causes extreme stimulation of the vestibular system and leads to the faulty perception that the aircraft is climbing.

plural of wagon-wheel effect

plural of ground effect machine

plural of ground-effect vehicle

plural of ground-effect machine