[ noun ]
a heavy odorless colorless gas formed during respiration and by the decomposition of organic substances; absorbed from the air by plants in photosynthesis
<noun.substance>

Carbonic \Car*bon"ic\, a. [Cf. F. carbonique. See {Carbon}.]
(Chem.)
Of, pertaining to, or obtained from, carbon; as, carbonic
oxide.

{Carbonic acid} (Chem.), an acid {HO.CO.OH}, not existing
separately, which, combined with positive or basic atoms
or radicals, forms carbonates. In common language the term
is very generally applied to a compound of carbon and
oxygen, {CO2}, more correctly called {carbon dioxide}. It
is a colorless, heavy, irrespirable gas, extinguishing
flame, and when breathed destroys life. It can be reduced
to a liquid and solid form by intense pressure. It is
produced in the fermentation of liquors, and by the
combustion and decomposition of organic substances, or
other substances containing carbon. It is formed in the
explosion of fire damp in mines, and is hence called
{after damp}; it is also know as {choke damp}, and
{mephitic air}. Water will absorb its own volume of it,
and more than this under pressure, and in this state
becomes the common soda water of the shops, and the
carbonated water of natural springs. Combined with lime it
constitutes limestone, or common marble and chalk. Plants
imbibe it for their nutrition and growth, the carbon being
retained and the oxygen given out.

{Carbonic oxide} (Chem.), a colorless gas, {CO}, of a light
odor, called more correctly {carbon monoxide}. It is
almost the only definitely known compound in which carbon
seems to be divalent. It is a product of the incomplete
combustion of carbon, and is an abundant constituent of
water gas. It is fatal to animal life, extinguishes
combustion, and burns with a pale blue flame, forming
carbon dioxide.


CO2 \CO2\ (s[=e]"[-o]*t[=oo]`), n.
the chemical formula for {carbon dioxide}, a heavy odorless
gas ({CO2}) formed during respiration and by the combustion
or decomposition of organic substances; it is absorbed from
the air by plants in photosynthesis. The formula itself,
pronounced out, is often used instead of the full name,
especially with reference to fire extinguishers using this
gas for fire suppression; as, a CO2 extinguisher.

Syn: carbon dioxide, carbonic acid gas.
[WordNet 1.5 +PJC]


CO2 \CO2\ (s[=e]"[-o]*t[=oo]`), n.
the chemical formula for {carbon dioxide}, a heavy odorless
gas ({CO2}) formed during respiration and by the combustion
or decomposition of organic substances; it is absorbed from
the air by plants in photosynthesis. The formula itself,
pronounced out, is often used instead of the full name,
especially with reference to fire extinguishers using this
gas for fire suppression; as, a CO2 extinguisher.

Syn: carbon dioxide, carbonic acid gas.
[WordNet 1.5 +PJC]