The Collaborative International Dictionary of English v.0.48:

Fee \Fee\ (f[=e]), n. [OE. fe, feh, feoh, cattle, property,
   money, fief, AS. feoh cattle, property, money; the senses of
   "property, money," arising from cattle being used in early
   times as a medium of exchange or payment, property chiefly
   consisting of cattle; akin to OS. fehu cattle, property, D.
   vee cattle, OHG. fihu, fehu, G. vieh, Icel. f[=e] cattle,
   property, money, Goth. fa['i]hu, L. pecus cattle, pecunia
   property, money, Skr. pa[,c]u cattle, perh. orig., "a
   fastened or tethered animal," from a root signifying to bind,
   and perh. akin to E. fang, fair, a.; cf. OF. fie, flu, feu,
   fleu, fief, F. fief, from German, of the same origin. the
   sense fief is due to the French. [root]249. Cf. Feud,
   Fief, Fellow, Pecuniary.]
   1. property; possession; tenure. "Laden with rich fee."
      --Spenser.
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            Once did she hold the gorgeous East in fee.
                                                  --Wordsworth.
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   2. Reward or compensation for services rendered or to be
      rendered; especially, payment for professional services,
      of optional amount, or fixed by custom or laws; charge;
      pay; perquisite; as, the fees of lawyers and physicians;
      the fees of office; clerk's fees; sheriff's fees; marriage
      fees, etc.
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            To plead for love deserves more fee than hate.
                                                  --Shak.
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   3. (Feud. Law) A right to the use of a superior's land, as a
      stipend for services to be performed; also, the land so
      held; a fief.
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   4. (Eng. Law) An estate of inheritance supposed to be held
      either mediately or immediately from the sovereign, and
      absolutely vested in the owner.
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   Note: All the land in England, except the crown land, is of
         this kind. An absolute fee, or fee simple, is land
         which a man holds to himself and his heirs forever, who
         are called tenants in fee simple. In modern writers, by
         fee is usually meant fee simple. A limited fee may be a
         qualified or base fee, which ceases with the existence
         of certain conditions; or a conditional fee, or fee
         tail, which is limited to particular heirs.
         --Blackstone.
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   5. (Amer. Law) An estate of inheritance belonging to the
      owner, and transmissible to his heirs, absolutely and
      simply, without condition attached to the tenure.
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   Fee estate (Eng. Law), land or tenements held in fee in
      consideration or some acknowledgment or service rendered
      to the lord.

   Fee farm (Law), land held of another in fee, in
      consideration of an annual rent, without homage, fealty,
      or any other service than that mentioned in the feoffment;
      an estate in fee simple, subject to a perpetual rent.
      --Blackstone.

   Fee farm rent (Eng. Law), a perpetual rent reserved upon a
      conveyance in fee simple.

   Fee fund (Scot. Law), certain court dues out of which the
      clerks and other court officers are paid.

   Fee simple (Law), an absolute fee; a fee without conditions
      or limits.
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            Buy the fee simple of my life for an hour and a
            quarter.                              --Shak.

   Fee tail (Law), an estate of inheritance, limited and
      restrained to some particular heirs. --Burill.
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The Collaborative International Dictionary of English v.0.48:

Fee \Fee\ (f[=e]), v. t. [imp. & p. p. Feed (f[=e]d); p. pr. &
   vb. n. Feeing.]
   To reward for services performed, or to be performed; to
   recompense; to hire or keep in hire; hence, to bribe.
   [1913 Webster]

         The patient . . . fees the doctor.       --Dryden.
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         There's not a one of them but in his house
         I keep a servant feed.                   --Shak.
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WordNet (r) 3.0 (2006):

fee
    n 1: a fixed charge for a privilege or for professional services
    2: an interest in land capable of being inherited
    v 1: give a tip or gratuity to in return for a service, beyond
         the compensation agreed on; "Remember to tip the waiter";
         "fee the steward" [syn: tip, fee, bung]

Moby Thesaurus II by Grady Ward, 1.0:

112 Moby Thesaurus words for "fee":
   Trinkgeld, account, admission, admission fee, allowance, anchorage,
   assessment, bill, blackmail, blood money, bonus, bounty, bribe,
   brokerage, carfare, cellarage, charge, charges, compensate,
   consideration, copyhold, cost, cover charge, demand, dockage,
   donative, double time, dues, emolument, entrance fee,
   equitable estate, estate at sufferance, estate for life,
   estate for years, estate in expectancy, estate in fee,
   estate in possession, estate tail, exaction, exactment, expense,
   fare, fee simple, fee tail, feod, feodum, feud, feudal estate,
   fief, footing, gratuity, gravy, grease, guerdon, hire, honorarium,
   hush money, incentive pay, indemnify, inducement, initiation fee,
   lagniappe, largess, lease, leasehold, legal estate, liberality,
   license fee, mileage, palm oil, paramount estate,
   particular estate, pay, pay by installments, pay on, perks,
   perquisite, pilotage, portage, pourboire, premium, prepay, price,
   reckoning, recompense, remainder, remit, remunerate, render,
   retainer, retaining fee, reversion, reward, salary, salvage, salve,
   satisfy, scot, scot and lot, shot, something extra, sportula,
   stipend, storage, sweetener, tender, tip, toll, towage, tribute,
   vested estate, wharfage



Bouvier's Law Dictionary, Revised 6th Ed (1856):

FEE, FEODUM or FEUDUM, estates. From the French, fief. A fee is an estate
which may continue forever. The word fee is explained to signify that the
land, or other subject of property, belongs to its owner, and is
transmissible, in the case of an individual, to those whom the law appoints
to succeed him, under the appellation of heirs; and in the case of corporate
bodies, to those who are to take on themselves the corporate function; and
from the manner in which the body is to be continued, are denominated
successors. 1 Co. Litt. 1, 271, b; Wright's Ten. 147, 150; 2 Bl. Com. 104.
106; Bouv. Inst. Index h.t.
     2. Estates in fee are of several sorts, and have different
denominations, according to their several natures and respective qualities.
They 'may with propriety be divided into, 1. Fees simple. 2. Fees
determinable. 3. Fees qualified. 4. Fees conditional and 5. Fees tail.
     3.-1. A fee simple is an estate inlands or tenements which, in
reference to the ownership of individuals, is not restrained to any heirs in
particular, nor subject to any condition or collateral determination except
the laws of escheat and the canons of descent, by which it may, be
qualified, abridged or defeated. In other words, an estate in fee simple
absolute, is an estate limited to a person and his heirs general or
indefinite. Watk. Prin. Con. 76. And the omission of the word `his' will not
vitiate the estate, nor are the words "and assigns forever" necessary to
create it, although usually added. Co. Litt. 7, b 9, b; 237, b Plowd. 28, b;
29, a; Bro. Abr. Estates, 4. 1 Co. Litt. 1, b; Plowd. 557 2 Bl. Com. 104,
106 Hale's Analysis, 74. The word fee simple is sometimes used by the best
writers on the law as contrasted with estates tail. 1 Co. Litt. 19. In this
sense, the term comprehends all other fees as well as the estate, properly,
and in strict propriety of technical language, peculiarly' distinguished by
this appellation.
     4.-2. A determinable fee is an estate which may continue forever.
Plowd. 557; Shep. Touch. 97. It is a quality of this estate while it falls
under this denomination, that it is liable to be determined by some act or
event, expressed on its limitation, to circumscribe its continuance, or
inferred by the law as bounding its extent. 2 Bl. Com. 109. Limitations to a
man. and his heirs, till the marriage of such. a person shall take place;
Cro. Jac. 593; 10 Vin. Abr. 133; till debts shall be paid; Fearne, 187 until
a minor shall attain the age of twenty-one years 3 Atk. 74 Ambler, 204; 9
Mod. 28 10 Vin. Abr. 203. Feariae, 342; are instances of such a determinable
fee.
     5.-3. Qualified fee, is an interest given on its, first limitation,
to a man and to certain of his heirs, and not to extend to all of them
generally, nor confined to the issue of his body. A limitation to a man and
his heirs on the part of his father, affords an example of this species of
estate. Litt. 254 1 Inst. 27, a 220; 1 Prest. on Estates, 449.
     6.-4. A conditional fee, in the more general acceptation of the term,
is when, to the limitation of an estate a condition is annexed, which
renders the estate liable to be defeated. 10 Rep. 95, b. In this application
of the term, either a determinable or a qualified fee may at the same time
be a conditional fee. An estate limited to a man and his heirs, to commence
on the performance of a condition, is also frequently described by this
appellation. Prest. on East. 476; Fearne, 9.
     7.-5. As to fee-tail, see Tail.