sinking

from The Century Dictionary.

• noun A falling or settling downward; a subsidence.
• noun The process of excavating downward through the earth, as in mining, etc.
• noun In arch., sculp., etc., a depression; a place hollowed out, whether for decoration or to receive some other feature; a socket.
• noun In joinery:
• noun An angular groove or rabbet in the corner of a board.
• noun The operation of making or of finishing rabbets.
• Causing to sink, subside, or gradually disappear: as, a sinking weight; causing the sensation of sinking or fainting: as, a sinking apprehension or anxiety.
• noun In piquet, the manœuver of calling only a part of a combination, so as to conceal the strength of the hand for playing: usually resorted to only when the player knows his adversary has no better call.

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

• a. & n. from sink.
• See under Fund.
• (Founding) a riser from which the mold is fed as the casting shrinks. See Riser, n., 4.
• a pump which can be lowered in a well or a mine shaft as the level of the water sinks.

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

• verb Present participle of sink.
• noun The act or process of sinking.

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

• noun a feeling caused by uneasiness or apprehension
• noun a descent as through liquid (especially through water)
• noun a slow fall or decline (as for lack of strength)