The Legal Lexicographer Bouvier defines credit & debt as:

CREDIT, common law, contracts.

1. The ability to borrow, on the opinion conceived by the lender that he will be repaid. This definition includes the effect and the immediate cause of credit. The debt due in consequence of such a contract is also called a credit; as, administrator of an the goods, chattels, effects and credits, &c.
2. The time extended for the payment of goods sold, is also called a credit; as, the goods were sold at six months credit.
   
3. In commercial law, credit is understood as opposed to debit; credit is what is due to a merchant, debit, what is due by him
4. According to M. Duvergier, credit also signifies that influence acquired by intrigue connected with certain social positions. 20 Toull. n. 19. This last species of credit is not, of such value as to be the object of commerce. Vide generally, 5 Taunt. R. 338.
   

CREDITOR, persons, contracts.

1. A creditor is he who has a right to require the fulfilment of an obligation. or contract.
2. Creditors may; be divided into personal and real.
3. The former are so called, because their claims are mainly against the person, who can reach the property of their debtors only by; virtue ofthe general rule by which he who has become personally obligated, is bound to fulfill his engagements, with all his property acquired and to be acquired, Which is a common guaranty for all his creditors.
4. The latter are called real, because they have mortgages or other securities binding on the real estates of their debtors.
5. It is proper to state that personal creditors may be divided into two classes first, those who have a right on all the property of their debtors, without considering the origin, or the nature of their claims; secondly, those who, in consequence of some provision of law, are entitled to some special prerogative, either in the manner of recovery, or in the rank they are to hold among creditors; these are entitled to preference. As an example, may be mentioned the case of the United State; when they are creditors, they have always a preference in case of insolvent estates.
6. A creditor sometimes becomes so, unknown to his debtor, as is the case when the former receives an assignment of commercial; paper, the title to recover which may be conveyed either by endorsement, or, in some cases, by mere delivery. But in general it is essential there should be a privity of contract between the parties. Vide, generally, 7 Vin. Ab. 42; 3 Com. Dig. 343; 8 Com. Dig. 388; 1 Supp. to Ves. Jr. 302 2 Sup. to Ves. Jr. 305 Code, 7, 72, 6; Id. 8, 18; Dig 42, 6, 17; Nov. 97 ch. t3 Bouv. Inst. Index, h.t.

DEBT, contracts.

1. A sum of money due by certain and express agreement. 3 Bl. Com. 154. In a less technical sense, as in the "act to regulate arbitrations and proceedings in courts of justice" of Pennsylvania, passed the 21st of March, 1806, s. 5, it means an claim for money. In a still more enlarged sense, it denotes any kind of a just demand; as, the debts of a bankrupt. 4 S. & R. 506.
2. Debts arise or are proved by matter of record, as judgment debts; by bonds or specialties; and by simple contracts, where the quantity is fixed and specific, and does not depend upon any future valuation to settle it. 3 Bl. Com. 154; 2 Hill. R. 220.
3. According to the civilians, debts are divided into active and passive. By the former is meant what is due to us, by the latter, what we owe. By liquid debt, they understand one, the payment of which may be immediately enforced, and not one which is due at a future time, or is subject to a condition; by hypothecary debt is meant, one which is a lien over an estate and a doubtful debt, is one the payment of which is uncertain. Clef des Lois Rom. h.t.
4. Debts are discharged in various ways, but principally by payment. See Accord and Satisfaction; Bankruptcy; Confusion Compensation; Delegation; Defeasance; Discharge of a contract; Extinction; Extinguishment; Former recovery; Lapse of time; Novation; Payment; Release; Rescission; Set off.
5. In payment of debts, some are to be paid before others, in cases of insolvent estates first, in consequence of the character of the creditor, as debts due to the United States are generally to be first paid; and secondly, in consequence of the nature of the debt, as funeral expenses and servants' wages, which are generally paid in preference to other debts. See Preference; Privilege; Priority.

DEBT, remedies.

The name of an action used for the recovery of a debt eo nomine and in numero though damages are generally awarded for the detention of the debt; these are, however, in most instances, merely nominal. 1 H. Bl. 550; Bull. N. P. 167 Cowp. 588.

The subject will be considered with reference, 1. To the kind of claim or obligation on which this action may be maintained. 2. The form of the declaration. 3. The plea. 4. The judgment.

Debt is a more extensive remedy for the recovery of money than assumpsit or covenant, for it lies to recover money due upon legal liabilities, as, for money lent, paid, had and received, due on an account stated; Com. Dig. Dett, A; for work and labor, or for the price of goods, and a quantum valebant thereon; Com. Dig. Dett, B Holt, 206; or upon simple contracts, express or implied, whether verbal or written, or upon contracts under seal, or of record, or by a common informer, whenever the demand for a sum is certain, or is capable of being reduced to certainty. Bull. N. P. 167. It also lies to recover money due on, any specialty or contract under seal to pay money. Str. 1089; Com. Dig. Dett, A 4; 1 T. R. 40. This action lies on a record, or upon a judgment of a court of record; Gilb. Debt, 891; Salk. 109; 17 S. & R. 1; or upon a foreign judgment. 3 Shepl. 167; 3 Brev. 395. Debt is a frequent remedy on statutes, either at the suit of the party grieved, or of a common informer. Com. Dig. Action on Statute, E; Bac. Ab. Debt, A. See, generally, Bouv. Inst. Index, h.t.; Com. Dig. h.t.; Dane's Ab. h.t.. Vin. Ab. h.t.; Chit. Pl. 100 to 109; Selw. N. P. 553 to 682; Leigh's N. P. Index, h.t. Debt also lies, in the detinet, for goods; which action differs from detinue, because it is not essential in this action, as in detinue, that the property in any specific goods should be vested in the plaintiff, at the time the action is brought; Dy. 24 b; and debt in the debet and detinet may be maintained on an instrument by which the defendant is bound to pay a sum of money lent, which might have been discharged, on or before the day of payment, in articles of merchandise. 4 Yerg. R. 171; see, Com. Dig. Dett, A 5; Bac. Ab. Debt, F; 3 Wood. 103, 4; 1 Dall. R. 458.

When the action is on a simple contract, the declaration must show the consideration of the contract, precisely as in assumpsit; and it should state either a legal liability or an express agreement, though not a promise to pay the debt. 2 T. R. 28, 30. When the action is founded on a specialty or record, no consideration need be shown, unless the performance of the consideration constitutes a condition precedent, when performance of such consideration must be averred. When the action is founded on a deed, it must be declared upon, except in the case of debt for rent. 1 New R. 104.

The plea to an action of debt is either general or special. 1. The plea of general issue to debt on simple contracts, or on statutes, or when the deed is only matter of inducement, is nil debet. See Nil debet. In general, when the action is on a specialty, the plea denying the existence of the contract is non est factum; 2 Ld. Raym. 1500; to debt on record, nul tiel record. 16 John. 55. Other matters must, in general, be pleaded specially.

For the form of the judgment, see Judgment in debt. Vide Remedy.

DEBTEE.

1. One to whom a debt is due a creditor, as, debtee executor. 3 Bl. Com. 18.

DEBTOR, contracts.

1. One who owes a debt; he who may be constrained to pay what he owes.
2. A debtor is bound to pay his debt personally, and all the estate he possesses or may acquire, is also liable for his debt.
3. Debtors are joint or several; joint, when they all equally owe the debt in solido; in this case if a suit should be necessary to recover the debt, all the debtors must be sued together or, when some are dead, the survivors must be sued, but each is bound for the whole debt, having a right to contribution from the others; they are several, when each promises severally to pay the whole debt; and obligations are generally binding on both or all debtors jointly and severally. When they are severally bound each may be sued separately, and on the payment of debt by one, the others will be bound to contribution, where all had participated in the money or property, which was the cause of the debt.
4. Debtors are also principal and surety; the principal debtor is bound as between him and his surety to pay the whole debt. and if the surety pay it, he will be entitled to recover against the principal. Vide Bouv. Inst. Index, h.t.; Vin. Ab. Creditor and Debtor; Id. Debt; 8 Com. Dig. 288; Dig. 50, 16, 108 Id. 50, 16, 178, 3; Toull. liv. 2, n. 250.

Sources:

• Mojo Law