reserve

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

• transitive verb To keep back, as for future use or for a special purpose.
• transitive verb To set or cause to be set apart for a particular person or use: synonym: book.
• transitive verb To keep or secure for oneself; retain: synonym: keep.
• noun Something kept back or saved for future use or a special purpose.
• noun An amount of capital that is not invested or otherwise used in order to meet probable demands, such as withdrawals by bank depositors or claims on insurance policies.
• noun Lack of enthusiasm, as from a misgiving or doubt.
• noun Self-restraint in expression or bearing; reticence or coolness.
• noun A reservation of public land.
• noun An amount of a mineral, fossil fuel, or other resource known to exist in a particular location and to be exploitable.
• noun A fighting force kept uncommitted until strategic need arises.
• noun The part of a country's armed forces not on active duty but subject to call in an emergency.
• noun A member of either of these forces.
• noun A group of players that play only as substitutes for starters in games or are kept from playing for some reason.
• noun One of these players.
• adjective Held in or forming a reserve.
• idiom (in reserve) Kept back, set aside, or saved.

from The Century Dictionary.

• noun In postal service, a fixed amount of cash retained at a money-order station to meet orders payable at that station.
• In ecclesiastical, to retain or preserve (a portion of the consecrated elements) for certain purposes.
• To keep back; keep in store for future or other use; preserve; withhold from present use for another purpose; keep back for a time: as, a reserved seat.
• To preserve; keep safe; guard.
• To make an exception of; except, as from the conditions of an agreement.
• Synonyms Reserve, Retain, etc. See keep.
• noun The act of reserving or keeping back.
• noun That which is reserved or kept for other or future use; that which is retained from present use or disposal.
• noun Something in the mind withheld from disclosure; a reservation.
• noun Self-imposed restraint of freedom in words or actions; the habit of keeping back or restraining the feelings; a certain closeness or coldness toward others; caution in personal behavior.
• noun An exception; something excepted.
• noun In law, reservation.
• noun In banking, that part of capital which is retained in order to meet average liabilities, and is therefore not employed in discounts or temporary loans. See bank, 4.
• noun Milit.:
• noun The body of troops, in an army drawn up for battle, reserved to sustain the other lines as occasion may require; a body of troops kept for an exigency.
• noun That part of the fighting force of a country which is in general held back, and upon which its defense is thrown when its regular forces are seriously weakened or defeated: as, the naval reserve.
• noun A magazine of warlike stores situated between an army and its base of operations.
• noun In theology, the system according to which only that part of the truth is set before the people which they are regarded as able to comprehend or to receive with benefit: known also as economy. Compare discipline of the secret, under discipline.
• noun In calico-printing and other processes, same as resist, 2.
• noun Same as reservation, 3.
• noun Synonyms Retention.
• noun Restraint, distance.

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

• noun The act of reserving, or keeping back; reservation.
• noun That which is reserved, or kept back, as for future use.
• noun That which is excepted; exception.
• noun Restraint of freedom in words or actions; backwardness; caution in personal behavior.
• noun A tract of land reserved, or set apart, for a particular purpose
• noun A body of troops in the rear of an army drawn up for battle, reserved to support the other lines as occasion may require; a force or body of troops kept for an exigency.
• noun troops trained but released from active service, retained as a formal part of the military force, and liable to be recalled to active service in cases of national need (see Army organization, above).