1 to say what medicine or treatment sb should have 开药(方);处方:
Can you prescribe something for my cough please, doctor?医生,请你给我开一些咳嗽药,可以吗?
2 (formal 正式) (used about a person or an organization with authority) to say that sth must be done (指有权力的人或机构)规定,指定:
The law prescribes that the document must be signed in the presence of two witnesses.法律规定这份文件必须在有两名见证人在场的情况下签署。