barn

barn (b),

(barn),

A unit of area for effective cross-section of atomic nuclei with respect to atomic projectiles; equal to 10^-24 cm².

[fr. "big as the side of a barn" by humorous comparison with much smaller areas]

A unit of area—10–24 cm2—for the effective cross-section of atomic nuclei; barns indicate the cross-sectional area in which atomic, nuclear, and particle interactions occur

BARN

Bilateral acute retinal necrosis Ophthalmology A condition characterized by herpes virus-induced anterior and posterior uveitis, papillitis with retinal detachment 1-3 months after onset, of which only 50% are bilateral. See Herpes.