Important Terms of the French Revolution
First Estate - The clergy, both high and low.
Second Estate - The nobility. Technically, but not usually of much relevance, the Second Estate also included the Royal Family.
Third Estate - Everyone not included in the First or Second Estate. At times this term refers specifically to the Bourgeoisie, the middle class, but the Third Estate also included the Sans-culottes, the laboring class.

Social classes

Royalty - Usually refers to the House of Bourbon, but can also refer to Napoleon Bonaparte and his family after the Empire was established.
Nobility (Fr. noblesse) - Those with explicit noble title. These are traditionally divided into "noblesse d'epee" ("nobility of the sword") and "noblesse de la robe" ("nobility of the gown"), the magisterial class that administered royal justice and civil government.
Ci devant nobility - Literally "from before": nobility of the ancien régime (the Bourbon monarchy), as against nobles later created by Napoleon Bonaparte.
Bourgeoisie - Roughly, the non-noble wealthy, typically merchants, investors, and professionals such as lawyers.
Sans-culottes - literally "those without breeches", the masses of Paris.
Peasants.

Political Groupings

Royalists or Monarchists - Generally refers specifically to supporters of the Bourbon monarchy and can include both supporters of absolute and constitutional monarchy. See Reactionary.
Jacobins - strictly, a member of the Jacobin club, but more broadly any revolutionary, particularly the more radical bourgeois elements.
Feuillants - Members of the Club des Feuillants, result of a split within the Jacobins, who favored a constitutional monarchy over a republic.
Republicans - Advocates of a system without a monarch.
The Gironde - Technically, a group of twelve republican deputies more moderate in their tactics than the Montagnards, though arguably many were no less radical in their beliefs; the term is often applied more broadly to others of similar politics. Members and adherents of the Gironde are variously referred to as "Girondists" (Fr. "Girondins") or "Brissotins"
The Mountain (Fr. Montagne) - The radical republican grouping in power during the Reign of Terror; its adherents are typically referred to as "Montagnards".
Thermidorians or Thermidoreans- The more moderate (some would say reactionary) grouping that came to power after the fall of the Mountain.
Society of the Panthéon, a.k.a. Conspiracy of the Equals, a.k.a. Secret Directory - faction centered around François-Noël Babeuf, who continued to hold up a radical Jacobin viewpoint during the period of the Thermidorian reaction.
Bonapartists - Supporters of Napoleon Bonaparte, especially those who supported his taking on the role of Emperor.
Émigrés - This term usually refers to those conservatives and members of the elite who left France in the period of increasingly radical revolutionary ascendancy, usually under implied or explicit threat from the Terror. (Generically, it can refer to those who left at other times or for other reasons.) Besides the émigrés having their property taken by the State, relatives of émigrés were also persecuted.

The "Great Fear" - Refers to the period of July and August 1789, when peasants sacked the castles of the nobles and burned the documents that recorded their feudal obligations.

Summary of The Reign of Terror

The Reign of Terror (June 1793 - July 1794) was a period in the French Revolution characterized by brutal repression (The Terror; see also state terrorism) from a highly centralized political regime, that suspended most of the democratic achievement of the Revolution and intended to pursue the Revolution on social matters, to destroy the internal enemies and conspirators and to oust the external enemies from French territory.

The Terror as such started on September 5, 1793 and, as the Reign of Terror, lasted until the summer of 1794, and killed (estimates vary wildly) anywhere between 18,000 to 40,000 people. In the single month before it ended, 1,300 executions took place.

In the summer of 1793 the French Revolution was threatened both by internal enemies and conspirators, and by foreign European monarchies fearing that the Revolution would spread. Almost all European governments in those days were based on royal sovereignty, whether absolute or constitutional, rather than the popular sovereignty asserted by the revolutionary French. The Powers wanted to stifle the democratic and republican ideas. Their armies were pressing on the border of France (see French Revolutionary Wars). The former French nobility, having lost its inherited privileges, had a stake in the failure of the revolution. The Catholic Church was also generally hostile to the Revolution, which (through the Civil Constitution of the Clergy) turned the clergy into employees of the state, requiring them take an oath of loyalty to the nation. About half the clergy, mainly in western France, refused the oath, becoming known as refractory priests or non-jurors. Understandably, these Catholic priests and the former nobility entered into conspiracies, often invoking foreign military intervention. In the western region known as Vendée an insurrection, led by priests and former nobles, was started in the spring of 1793. The extension of civil war and the advance of foreign armies on national territory produced a political crisis, increasing the rivalry between the Girondins and the more radical Jacobins, with the latter having the support of the Parisian population.

Facing local revolts and foreign invasions both in East and West of the country, the most urgent government business was the war. On August 17, the Convention voted general conscription, the levée en masse, which mobilized all citizens to serve as soldiers or suppliers in the war effort. On September 5, the Convention, pressured by the people of Paris, institutionalized The Terror: systematic and lethal repression of perceived enemies within the country.

The result was a policy through which the state used violent repression to crush resistance to the central government. Under control of the effectively dictatorial Committee, the Convention quickly enacted more legislation. On September 9, the Convention established sans-culotte paramilitary forces, the revolutionary armies, to force farmers to surrender grain demanded by the government. On September 17, the Law of Suspects was passed, which authorized the charging of counter-revolutionaries with vaguely defined crimes against liberty. On September 29, Convention extended price-fixing from grain and bread to other essential goods and fixed wages.

The heads begin to fall under the guillotine: the Queen Marie-Antoinette, the Girondins, Philippe Égalité despite his vote for the death of the King, Madame Roland and many others. The Revolutionary Tribunal summarily condemned thousands of suspects to death by the guillotine. Mobs beat some victims to death. Sometimes people died for their political opinions or actions, but often for little reason whatsoever beyond mere suspicion, or because some others had a stake in getting rid of them. Most of the victims received an unceremonious trip to the guillotine in an open wooden cart (the tumbrel). Loaded on these carts, the victims would proceed through throngs of jeering men and women.

The Reign of Terror was able to save the revolutionary government from military defeat. The Jacobins expanded the size of the army and Carnot replaced many aristocratic officers with younger soldiers who had demonstrated their ability and patriotism. The republican army threw back the Austrians, Prussians, English, and Spanish during the autumn. At the end of 1793, the republican army began to prevail and the provincial revolts were defeated one by one. The Terror became identified with ruthless but centralized revolutionary government. The economical dirigiste program didn't solve the problems. Suspect goods are confiscated by the Decrets of Ventôse (February-March 1794), in order to prepare the redistribution of wealth.

The centralization of repression also brought thousands of victims before the Paris Revolutionary Tribunal, whose work was expedited by the draconian Law of 22 Prairial (June 10, 1794) which led to The Great Terror. As a result of Robespierre's insistence on associating Terror with Virtue, his efforts to make the republic a morally united patriotic community became equated with the endless bloodshed. Finally, after June 26's decisive military victory over the Austrians at the Battle of Fleurus, Robespierre was overthrown by a conspiracy of certain members of the Convention on 9 Thermidor (July 27). After trying in vain to raise Paris, the Robespierrist deputies and most members of the Commune were guillotined the next day, July 28. Thus began the Thermidorian reaction, an era of relaxation after the excesses of the Terror, with the establishment of the Directory form of government.

All information taken from the French Revolution Glossary on World IQ.com

http://www.wordiq.com/definition/Glossary_of_the_French_Revolution#Social_classes