| 释义 |
del·ta
I. \ˈdeltə\ noun
(-s)
Etymology: Middle English deltha, from Greek delta, of Semitic origin; akin to Hebrew dāleth 4th letter of the Hebrew alphabet — more at daleth
1. : the fourth letter of the Greek alphabet — symbol Δ or δ; see alphabet table
2. : any of various things felt to resemble a capital Δ: as
a. : the alluvial deposit at the mouth of a river commonly forming a nearly flat fan-shaped plain of considerable area traversed by many separate branches in which the river distributes itself downstream and resulting from the accumulation of stream-borne sediment supplied more rapidly than it can be carried away by offshore and alongshore currents
b. : the closed figure produced by connecting three electrical coils or circuits successively end for end especially in a three-phase system
c. : the triangular terminus of a pattern in a fingerprint formed either by bifurcation of a ridge or by divergence of two ridges that are parallel beyond it
3. : an increment of a variable — symbol Δ
II.
Usage: usually capitalized
— a communications code word for the letter d
III. adjective
or δ- \“\
1. : of or relating to one of four or more closely related chemical substances
< δ-yohimbine >
— used somewhat arbitrarily to specify ordinal relationship or to specify a particular physical form, especially an allotropic modification (as in δ-iron), or an isomeric or stereoisomeric form (as in δ-benzene hexachloride)
2. : fourth in position in the structure of an organic molecule from a particular group or atom or having a structure characterized by such a position
< δ-hydroxy acids >
< δ-lactones >
3. : fourth in order of brightness — used of a star in a constellation
IV. adjective
Usage: often capitalized
: of, relating to, or characteristic of the region of the alluvial plain east of the Mississippi River in western Mississippi
< delta blues > |