[Note that I am not a professional specialist in either history or literature, and that those who are might insist on adding further qualifications and refinements to the following basic account; also, the special senses in which some of these terms are used by antique furniture dealers will generally not be discussed below.]
 

Jane Austen is very resistant to being classified as part of a literary "school", or being placed in any customarily-defined literary period -- partly because none of the obvious available terms, "18th-century, "Romantic", or "Victorian", would appropriately describe her. Almost all of the major figures who were literarily active in the period 1800-1837, and who are currently deemed worthy of remembering (i.e. are "canonized"), fall into one of a few categories -- either they launched their literary careers before 1800 (Burney, Edgeworth); or they were part of the Romantic movement (or were more or less strongly influenced by romanticism, or wrote in self-conscious reaction to romanticism); or they did most of their writing and publishing after 1837 (e.g. Dickens). Jane Austen is the conspicuous exception who does not fit into any of these categories.

One subscriber to AUSTEN-L has reported not having an opportunity to study Austen in college for exactly this reason: the professor who taught the course on 18th-century literature didn't consider Jane Austen relevant to that course, and neither did the professor who taught the next in the sequence of literature "survey" courses (presumably on Romantic and/or Victorian literature) -- so that as a result, Jane Austen wasn't covered at all!

The following list defines many of the chronological or quasi-chronological terms relevant to Jane Austen's era:

"Eighteenth century"
This obviously covers the years 1700-1799 (or the years 1701-1800, according to some pedantic definitions).
On the one hand, Jane Austen was born in 1775; she does have similarities to some authors that are classified as "18th century"; starting in the mid-to-late 1780's she wrote short humorous pieces for her family, and early versions of three of her later novels; and one of her novels (Northanger Abbey) is set in 1798-1799. But she didn't sell a novel until 1803, her first actual publication was in 1811, and all of the novels whose first drafts had been written before 1800 were revised by her after 1809 before they were published -- so that her most important period of literary activity was 1810-1817, for which "18th century" doesn't seem to be a very accurate description (unless perhaps a loose "extended 18th century" is defined).
"Romantic"
The term "Romantic" can be used in a general chronological sense (covering the late 18th century and the first half of the nineteenth century, the main heyday of romanticism); but it can only be used to describe individual artists if they were influenced significantly by romanticism -- which Jane Austen was not. ("Do not be angry with me for beginning another letter to you. I have read [Byron's] The Corsair, mended my petticoat, and have nothing else to do." -- Jane Austen, letter of March 5, 1814 to her sister Cassandra.)
"How to Be a Romantic Poet"
"Victorian"
Victoria acceded to the throne in 1837, was crowned 1838, and died in 1901. (Jane Austen died more than a year before Victoria was even born.)
"Regency"
Strictly speaking, the Regency is the period 1811-1820 when King George III was declared incapacitated (due to insanity), and the Prince of Wales (later George IV) acted as Regent. However, the term is often loosely used to cover the Directoire and Empire periods as well (one reason to do this is that these periods seem to group together as a unit socially -- for example the period of about 1795-1820 is when women's clothing styles were somewhat classically-influenced and relatively less cumbersome in basic outline -- and see also the discussion of the chronology of the wars below).
Go to illustrations of the "extended" Regency period.

Some historians of architecture and antique furniture dealers also seem to use "Regency" as a loose term for everything between 18th-century and Victorian.
While "Regency" is the word which best describes Jane Austen's writing career in purely chronological terms, this word has not traditionally been used to label a literary era (there is no conventionally-recognized "Regency" school of writers).

"Directoire"
The period from 1795-1799, especially in France (which was then ruled by a directorate of five, later three, men).
"Empire"
The period of Napoleon's declared Empire, from 1804 to 1814/1815 (or starting from 1800, if one includes his "Consulate").
"Federal"
Insofar as this has an exact meaning, it would refer to the period from 1788/1789 to 1801 -- between the establishment of the U.S. Constitution and Thomas Jefferson's coming into the office of President as a "Republican" (having triumphed over the "Federalist" John Adams) -- though dealers in antique furniture apparently use this term in a somewhat different sense.
"Georgian"
Monarchs named George reigned in Great Britain from 1712 to 1830, but "Georgian" seems mostly to be used to refer to a style of eighteenth century architecture, or as a vague synonym for "Eighteenth Century" with special reference to Britain.
"Revolutionary and Napoleonic Wars"
France was involved in wars with other European powers (always including Great Britain) from 1792-1802, from 1803-1814, and during the "hundred days" in 1815. The wars of the French Revolution may be considered to last until perhaps about 1795, after which Napoleon began to take an increasingly prominent part in France's military affairs.
"Congress"
The period from the Congress of Vienna (begun 1814) to the last Congress (of Verona, 1822); the idea was that periodic diplomatic conferences would be held, at which European affairs would be settled -- particularly by the five big European powers (Great Britain, France, Austria, Russia, and Prussia).
(Note that the terms "Regency", "Georgian", and "Victorian" come from British political history, "Directoire" and "Empire" from France, and "Federal" from the U.S. -- which can affect how these terms are used.)
 
 
 

(From Republic of Pemberley : http://www.pemberley.com)