|
A decade is a period of 10 years. The word is derived (via French and Latin) from the Ancient Greek ''dekas'' which means ten. Other words for spans of years also come from Latin: biennium, triennium, quadrennium, quinquennium (5 years), lustrum (5 years), century (100 years), millennium (1000 years). == Distinctions == Although any period of 10 years is a decade,〔(【引用サイトリンク】title=Oxford Dictionaries )〕〔(Webster dictionary definition of "decade" )〕 a convenient and frequently referenced interval is based on the tens digit of a calendar year, as in using "1960s" to represent the decade from 1960 to 1969.〔(The OWL at Purdue: Apostrophe )〕〔(【引用サイトリンク】title=1960s )〕 Often, for brevity, only the tens part is mentioned (''60s'' or ''sixties''), although this may leave it uncertain which century is meant. These references are frequently used to encapsulate popular culture or other widespread phenomena that dominated such a decade, as in ''The Great Depression of the 1930s''. Because the common calendar starts with year 1, its ''first'' full decade is the years 1 to 10, the ''second'' decade from 11 to 20, and so on.〔''Passim'', i.a. Spencer, Donald D. 1989. ''Invitation to number theory with Pascal''. Ormond Beach: Camelot. 46: "The first decade is from 1 to 10 inclusive, the second decade from 11 to 20 inclusive, and so on."〕 So although the "1960s" comprises the years 1960 to 1969, the "197th decade" spans 1961 to 1970. A decade may also refer to an arbitrary span of 10 years. For example, the statement "during his last decade, Mozart explored chromatic harmony to a degree rare at the time", merely refers to the last 10 years of Mozart's life without regard to which calendar years are encompassed. For decades of the 20th century, the term 'decade' often conjures not just a set of ten years but a distinct era roughly approximating those ten years - for example, ''the sixties'' often refer to events that took place between c. 1964 and 1972 and conjure memories of the counterculture, flower power, protests of 1968 and other things going on at the time. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Decade」の詳細全文を読む スポンサード リンク
|