Dic: prescribe (2) (GIVE RULE)

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2. If a person or set of laws or rules prescribes an action or duty, they state that it must be carried out. (FORMAL)

• ...article II of the constitution, which prescribes the method of electing a president...
• Alliott told Singleton he was passing the sentence prescribed by law.

.... COBUILD

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verb [T] FORMAL △to tell someone what they must have or do; to give something as a rule:

• Penalties for not paying taxes are prescribed by law. 
• [+ that] The law prescribes that all children must go to school. 
• [+ question word] Grammatical rules prescribe how words may be used together.

▷ prescribed. adj:

• The product will have to meet internationally prescribed (= demanded) standards.

▷ prescription. noun [C or U] FORMAL △when someone says what someone else must have or do:

• So what is his prescription for success?

▷ prescriptive. adj. FORMAL MAINLY DISAPPROVING △saying exactly what must happen, especially by giving an instruction or making a rule:

• Most teachers think the government's guidelines on homework are too prescriptive.

CF. prescribe(1) (GIVE MEDICAL TREATMENT)

.... CALD

■ prescriptive. adj.

 △ A prescriptive approach to something involves telling people what they should do, rather than simply giving suggestions or describing what is done. (FORMAL)

• ...prescriptive attitudes to language on the part of teachers...
• The psychologists insist, however, that they are not being prescriptive.

 △ 

1. making or giving directions, rules, or injunctions
2. sanctioned by long-standing usage or custom
3. derived from or based upon legal prescription: ex) a prescriptive title

  △ 

1. saying how something should or must be done, or what should be done: ex) prescriptive teaching methods 
2. stating how a language should be used, rather than describing how it is used (≠ descriptive) : ex) prescriptive grammar 
3. prescriptive right: BrE. law. a right that has existed for so long that it is as effective as a law

..... COBUILD, COLLINS, LDOCE