parameter
/pəˈræmɪtə(r)/noun
1- technical a numerical or other measurable factor forming one of a set that defines a system or sets the conditions of its operation〈技〉参（变）数; 参（变）量。
1.1
- Mathematics a quantity whose value is selected for the particular circumstances and in relation to which other variable quantities may be expressed【数】参数。
1.2
- Statistics a numerical characteristic of a population, as distinct from a statistic of a sample【统计】人口参数。
1.3
- (in general use) a limit or boundary which defines the scope of a particular process or activity（普通用法）范围, 界限：
the parameters within which the media work.
媒体的活动范围。
USAGE
Until recently, use of the word parameter was confined to mathematics and related technical fields. Since around the mid 20th century, however, it has been used in non-technical fields as a technical-sounding word for 'a limit or boundary', as in they set the parameters of the debate. This use, probably influenced by the word perimeter, has been criticized for being a weakening of the technical sense. However, it is now generally accepted as part of standard English.
词源
mid 17th cent.: modern Latin, from Greek para- 'beside' + metron 'measure'.