ˈdeltə n. 1 a
triangular tract of deposited
earth,
alluvium,
etc., at
the mouth of a
river, formed by
its diverging outlets. 2 a the
fourth letter of the
Greek alphabet. b a fourth-class mark
given for a
piece of
work or in an
examination. 3 Astron. the fourth
star in a
constellation. 4
Math. an
increment of a
variable. ødelta
connection Electr. a triangular
arrangement of three-phase windings
with circuit wire from each angle. delta rays
Physics rays of low penetrative
power consisting of
slow electrons ejected from an
atom by the
impact of ionizing
radiation. delta
rhythm (or wave) low-frequency
electrical activity of the
brain during sleep. delta
wing the triangular swept-back wing of an
aircraft. øødeltaic adj. [ME f. Gk f. Phoen. daleth]