vælv n. 1 a
device for controlling
the passage of
fluid through a
pipe etc.,
esp. an
automatic device allowing
movement in
one direction only. 2 Anat. & Zool. a membranous
part of an
organ etc. allowing a
flow of
blood etc. in one direction only. 3
Brit. =
thermionic valve. 4 a device to
vary the
effective length of the
tube in a
brass musical instrument. 5
each of the
two shells of an
oyster,
mussel, etc. 6
Bot. each of the segments
into which a
capsule or
dry fruit dehisces. 7
archaic a
leaf of a folding
door. øøvalvate adj. valved adj. (also in comb.). valveless adj. valvule n. [ME f. L valva leaf of a folding door]