{Pear blight}.
(a) (Bot.) A name of two distinct diseases of pear trees,
both causing a destruction of the branches, viz., that
caused by a minute insect ({Xyleborus pyri}), and that
caused by the freezing of the sap in winter. --A. J.
Downing.
(b) (Zo["o]l.) A very small beetle ({Xyleborus pyri}) whose
larv[ae] bore in the twigs of pear trees and cause them
to wither.
{Pear family} (Bot.), a suborder of rosaceous plants
({Pome[ae]}), characterized by the calyx tube becoming
fleshy in fruit, and, combined with the ovaries, forming a
pome. It includes the apple, pear, quince, service berry,
and hawthorn.
{Pear gauge} (Physics), a kind of gauge for measuring the
exhaustion of an air-pump receiver; -- so called because
consisting in part of a pear-shaped glass vessel.
{Pear shell} (Zo["o]l.), any marine gastropod shell of the
genus {Pyrula}, native of tropical seas; -- so called from
the shape.
{Pear slug} (Zo["o]l.), the larva of a sawfly which is very
injurious to the foliage of the pear tree.