ink

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A pigmented liquid or paste used especially for writing or printing.
• noun A dark liquid ejected for protection by most cephalopods, including octopuses and squids.
• noun Informal Coverage in the print media; publicity.
• noun Informal A tattoo or tattoos.
• transitive verb To mark, coat, or stain with ink.
• transitive verb Informal To append one's signature to (a contract, for example).
• transitive verb Informal To tattoo.

from The Century Dictionary.

• To color with ink.
• To spread ink over; daub with ink.
• noun In falconry, the neck, or that part from the head to the body of the bird that a hawk preys upon.
• noun The socket of a mill-spindle.
• noun A colored fluid of slight viscosity used for writing or drawing, or a more viscous colored substance used in printing: distinguished as writing-ink and printing-ink.
• noun In zoology, the inky fluid of a cephalopod, as the cuttlefish.
• noun A mixture of lampblack and turpentine used with a brush or stencil for marking packing-cases and other packages.
• noun A writing-ink which cannot be changed by chemicals.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Mach.) The step, or socket, in which the lower end of a millstone spindle runs.
• transitive verb To put ink upon; to supply with ink; to blacken, color, or daub with ink.
• noun A fluid, or a viscous material or preparation of various kinds (commonly black or colored), used in writing or printing.
• noun A pigment. See India ink, under India.
• noun a peculiar ink used for writings of which copies by impression are to be taken.
• noun (Zoöl.) an ink sac.
• noun (Bot.) The West Indian indigo berry. See Indigo.
• noun (Bot.) a New Zealand shrub (Coriaria thymifolia), the berries of which yield a juice which forms an ink.
• noun a powder from which ink is made by solution.
• noun (Zoöl.) 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.
• noun See under Printing.
• noun 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.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A pigment (or dye)-based fluid used for writing, printing etc.
• noun countable A particular type, color or container of this fluid.
• noun The black or dark-colored fluid ejected by squid, octopus etc, as a protective strategy.
• noun slang, uncountable Publicity.
• noun slang, uncountable Tattoo work.
• noun slang Cheap red wine.
• verb transitive To apply ink to; to cover or smear with ink.
• verb transitive To sign (a document) (with or as if with ink).
• verb transitive To apply a tattoo to (someone).

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb append one's signature to
• noun dark protective fluid ejected into the water by cuttlefish and other cephalopods
• verb fill with ink
• noun a liquid used for printing or writing or drawing
• verb mark, coat, cover, or stain with ink