blu

a. [ Compar. Bluer superl. Bluest. ] [ OE. bla, blo, blew, blue, livid, black, fr. Icel.blār livid; akin to Dan. blaa blue, Sw. blå, D. blauw, OHG. blāo, G. blau; but influenced in form by F. bleu, from OHG. blāo. ] 1. Having the color of the clear sky, or a hue resembling it, whether lighter or darker; as, the deep, blue sea; as blue as a sapphire; blue violets. “The blue firmament.” Milton. [ 1913 Webster ]

2. Pale, without redness or glare, -- said of a flame; hence, of the color of burning brimstone, betokening the presence of ghosts or devils; as, the candle burns blue; the air was blue with oaths. [ 1913 Webster ]

3. Low in spirits; melancholy; as, to feel blue. [ 1913 Webster ]

4. Suited to produce low spirits; gloomy in prospect; as, thongs looked blue. [ Colloq. ] [ 1913 Webster ]

5. Severe or over strict in morals; gloom; as, blue and sour religionists; suiting one who is over strict in morals; inculcating an impracticable, severe, or gloomy mortality; as, blue laws. [ 1913 Webster ]

6. Literary; -- applied to women; -- an abbreviation of bluestocking. [ Colloq. ] [ 1913 Webster ]

The ladies were very blue and well informed. Thackeray. [ 1913 Webster ]

Blue asbestus. See Crocidolite. --
Blue black, of, or having, a very dark blue color, almost black. --
Blue blood. See under Blood. --
Blue buck (Zool.), a small South African antelope (Cephalophus pygmæus); also applied to a larger species (Ægoceras leucophæus); the blaubok. --
Blue cod (Zool.), the buffalo cod. --
Blue crab (Zool.), the common edible crab of the Atlantic coast of the United States (Callinectes hastatus). --
Blue curls (Bot.), a common plant (Trichostema dichotomum), resembling pennyroyal, and hence called also bastard pennyroyal. --
Blue devils, apparitions supposed to be seen by persons suffering with delirium tremens; hence, very low spirits. “Can Gumbo shut the hall door upon blue devils, or lay them all in a red sea of claret?” Thackeray. --
Blue gage. See under Gage, a plum. --
Blue gum, an Australian myrtaceous tree (Eucalyptus globulus), of the loftiest proportions, now cultivated in tropical and warm temperate regions for its timber, and as a protection against malaria. The essential oil is beginning to be used in medicine. The timber is very useful. See Eucalyptus. --
Blue jack,
Blue stone, blue vitriol; sulphate of copper. --
Blue jacket, a man-of war's man; a sailor wearing a naval uniform. --
Blue jaundice. See under Jaundice. --
Blue laws, a name first used in the eighteenth century to describe certain supposititious laws of extreme rigor reported to have been enacted in New Haven; hence, any puritanical laws. [ U. S. ] --
Blue light, a composition which burns with a brilliant blue flame; -- used in pyrotechnics and as a night signal at sea, and in military operations. --
Blue mantle (Her.), one of the four pursuivants of the English college of arms; -- so called from the color of his official robes. --
Blue mass, a preparation of mercury from which is formed the blue pill. McElrath. --
Blue mold or
Blue mould, the blue fungus (Aspergillus glaucus) which grows on cheese. Brande & C. --
Blue Monday, (a) a Monday following a Sunday of dissipation, or itself given to dissipation (as the Monday before Lent). (b) a Monday considered as depressing because it is a workday in contrast to the relaxation of the weekend. --
Blue ointment (Med.), mercurial ointment. --
Blue Peter (British Marine), a blue flag with a white square in the center, used as a signal for sailing, to recall boats, etc. It is a corruption of blue repeater, one of the British signal flags. --
Blue pill. (Med.) (a) A pill of prepared mercury, used as an aperient, etc. (b) Blue mass. --
Blue ribbon. (a) The ribbon worn by members of the order of the Garter; -- hence, a member of that order. (b) Anything the attainment of which is an object of great ambition; a distinction; a prize. “These [ scholarships ] were the blue ribbon of the college.” Farrar. (c) The distinctive badge of certain temperance or total abstinence organizations, as of the Blue ribbon Army. --
Blue ruin, utter ruin; also, gin. [ Eng. Slang ] Carlyle. --
Blue spar (Min.), azure spar; lazulite. See Lazulite. --
Blue thrush (Zool.), a European and Asiatic thrush (Petrocossyphus cyaneas). --
Blue verditer. See Verditer. --
Blue vitriol (Chem.), sulphate of copper, a violet blue crystallized salt, used in electric batteries, calico printing, etc. --
Blue water, the open ocean. --
Big Blue, the International Business Machines corporation. [ Wall Street slang. ] PJC --
To look blue, to look disheartened or dejected. --
True blue, genuine and thorough; not modified, nor mixed; not spurious; specifically, of uncompromising Presbyterianism, blue being the color adopted by the Covenanters. [ 1913 Webster ]

For his religion . . .
'T was Presbyterian, true blue. Hudibras. [ 1913 Webster ]