a valve for preventing flowing liquid, as sewage, from reversing its direction.
- Back focus
the distance between the back surface of a lens and the focal plane when the lens is focused at infinity.
- Back foot
noun on the back foot, at a disadvantage; outmanoeuvred or outclassed by an opponent Contemporary Examples Government forces, he says, are constantly on the back foot, rarely launching offensives to regain territory. Iraqis Swear: Baghdad Airport is Safe From ISIS Susannah George October 12, 2014 Historical Examples He pulled at his back foot like a […]
- Back formation
the analogical creation of one word from another word that appears to be a derived or inflected form of the first by dropping the apparent affix or by modification. a word so formed, as typewrite from typewriter. Historical Examples In any event, the men should be taught to take some form of a closed back […]
- Back four
noun (soccer) the defensive players in many modern team formations: usually two fullbacks and two centre backs