The Collaborative International Dictionary of English v.0.48:
Ink \Ink\, n. [OE. enke, inke, OF. enque, F. encre, L. encaustum
the purple red ink with which the Roman emperors signed their
edicts, Gr. ?, fr. ? burnt in, encaustic, fr. ? to burn in.
See Encaustic, Caustic.]
1. A fluid, or a viscous material or preparation of various
kinds (commonly black or colored), used in writing or
Make there a prick with ink. --Chaucer.
Deformed monsters, foul and black as ink. --Spenser.
2. A pigment. See India ink, under India.
Note: Ordinarily, black ink is made from nutgalls and a
solution of some salt of iron, and consists essentially
of a tannate or gallate of iron; sometimes indigo
sulphate, or other coloring matter, is added. Other
black inks contain potassium chromate, and extract of
logwood, salts of vanadium, etc. Blue ink is usually a
solution of Prussian blue. Red ink was formerly made
from carmine (cochineal), Brazil wood, etc., but
potassium eosin is now used. Also red, blue, violet,
and yellow inks are largely made from aniline dyes.
Indelible ink is usually a weak solution of silver
nitrate, but carbon in the form of lampblack or India
ink, salts of molybdenum, vanadium, etc., are also
used. Sympathetic inks may be made of milk, salts of
cobalt, etc. See Sympathetic ink (below).
Copying ink, a peculiar ink used for writings of which
copies by impression are to be taken.
Ink bag (Zool.), an ink sac.
Ink berry. (Bot.)
(a) A shrub of the Holly family (Ilex glabra), found in
sandy grounds along the coast from New England to
Florida, and producing a small black berry.
(b) The West Indian indigo berry. See Indigo.
Ink plant (Bot.), a New Zealand shrub (Coriaria
thymifolia), the berries of which yield a juice which
forms an ink.
Ink powder, a powder from which ink is made by solution.
Ink sac (Zool.), an organ, found in most cephalopods,
containing an inky fluid which can be ejected from a duct
opening at the base of the siphon. The fluid serves to
cloud the water, and enable these animals to escape from
their enemies. See Illust. of Dibranchiata.
Printer's ink, or Printing ink. See under Printing.
Sympathetic ink, a writing fluid of such a nature that what
is written remains invisible till the action of a reagent
on the characters makes it visible.