Statistics – Some Historical Definitions (1800-1900)

“Il y a, dans la statistique, deux choses qui se trouvent continuellement mélangées, und methode et une science. On emploie la statistique comme methode, toutes les fois que l’on compte on que l’on mesure quelque chose, par example, l’éndendue d’un district, le mobre de habitants d’un pays, la quantité ou le prix de certaines denrées, etc. […] Il y a, de plus, une science de la statistique. Elle consiste à savoir réunir les chiffres, les combiner et les calculer, de la manière la plus propre à conduire à des résultats certains. Mais ceci n’est, à propement parler qu’une branche de mathémetiques.“ (Alphonse P de Candolle, “Considérations sur le statistique des délits” 1833)

“There are two aspects of statistics that are continually mixed, the method and the science. Statistics are used as a method, whenever we measure something, for example, the size of a district, the number of inhabitants of a country, the quantity or price of certain commodities, etc. […] There is, moreover, a science of statistics. It consists of knowing how to gather numbers, combine them and calculate them, in the best way to lead to certain results. But this is, strictly speaking, a branch of mathematics." (Alphonse P de Candolle, “Considerations on Crime Statistics”, 1833)

"[statistics is] that department of political science which is concerned in collecting and arranging facts illustrative of the condition and resources of the state. To reason upon such facts and to draw conclusions from them is not within the province of statistics; but is the business of the statesman and of the political economist." (Penny Cyclopedia, 1842)

“Statistics has then for its object that of presenting a faithful representation of a state at a determined epoch.” (Adolphe Quetelet, 1849) 

"Observations and statistics agree in being quantities grouped about a Mean; they differ, in that the Mean of observations is real, of statistics is fictitious. The mean of observations is a cause, as it were the source from which diverging errors emanate. The mean of statistics is a description, a representative quantity put for a whole group, the best representative of the group, that quantity which, if we must in practice put one quantity for many, minimizes the error unavoidably attending such practice. Thus measurements by the reduction of which we ascertain a real time, number, distance are observations. Returns of prices, exports and imports, legitimate and illegitimate marriages or births and so forth, the averages of which constitute the premises of practical reasoning, are statistics. In short, observations are different copies of one original; statistics are different originals affording one ‘generic portrait’. Different measurements of the same man are observations; but measurements of different men, grouped round l’homme moyen, are prima facie at least statistics." (Francis Y Edgeworth, 1885) 

“[Statistics] are the only tools by which an opening can be cut through the formidable thicket of difficulties that bars the path of those who pursue the Science of man.” (Sir Francis Galton, “Natural Inheritance”, 1889)

Further definitions:
1901-1950
1951-2000
2001- …