5 N‑UNCOUNT [in/out of N ] If a machine or device is in operation , it is working. □ There are three ski lifts in operation.
6 PHRASE When a rule, system, or plan comes into operation or you put it into operation , you begin to use it. □ The Financial Services Act came into operation four years ago. □ Cheaper energy conservation techniques have been put into operation in the developed world.
op|era|tion|al /ɒ pəre I ʃən ə l/
1 ADJ [usu v-link ADJ ] A machine or piece of equipment that is operational is in use or is ready for use. □ The whole system will be fully operational by December.
2 ADJ [usu ADJ n] Operational factors or problems relate to the working of a system, device, or plan. □ We cannot give any more details at this stage for operational reasons. ● op|era|tion|al|ly ADV [oft ADV adj, ADV after v] □ The device had been used operationally some months previously.
op|era|tive /ɒ pərət I v/ (operatives )
1 ADJ [usu v-link ADJ ] A system or service that is operative is working or having an effect. [FORMAL ] □ The commercial telephone service was no longer operative.
2 N‑COUNT An operative is a worker, especially one who does work with their hands. [FORMAL ] □ In an automated car plant there is not a human operative to be seen.
3 N‑COUNT An operative is someone who works for a government agency such as the intelligence service. [mainly AM ] □ Naturally the CIA wants to protect its operatives.
4 PHRASE If you describe a word as the operative word , you want to draw attention to it because you think it is important or exactly true in a particular situation. □ As long as the operative word is 'greed', you can't count on people keeping the costs down.
op|era|tor ◆◇◇ /ɒ pəre I tə r / (operators )
1 N‑COUNT An operator is a person who connects phone calls at a telephone exchange or in a place such as an office or hotel. □ He dialled the operator and put in a call for Rome.
2 N‑COUNT [usu n N ] An operator is a person who is employed to operate or control a machine. □ …computer operators.
3 N‑COUNT An operator is a person or a company that runs a business. [BUSINESS ] □ …'Tele-Communications', the nation's largest cable TV operator.
4 N‑COUNT [usu adj N ] If you call someone a good operator , you mean that they are skilful at achieving what they want, often in a slightly dishonest way. [INFORMAL ] □ [+ in ] …one of the shrewdest political operators in the Arab World.
5 → see also tour operator COLLOCATIONS operator NOUN
2
noun + operator : computer, machine, train
adjective + operator : experienced, skilled
3
noun + operator : hotel, mobile phone, network, rail
op|er|et|ta /ɒ pəre tə/ (operettas ) N‑VAR An operetta is a light-hearted opera which has some of the words spoken rather than sung.
oph|thal|mic /ɒfθæ lm I k/ ADJ [ADJ n] Ophthalmic means relating to or concerned with the medical care of people's eyes. [FORMAL ] □ Ophthalmic surgeons are now performing laser surgery to correct myopia.
oph|thal|molo|gist /ɒ fθælmɒ lədʒ I st/ (ophthalmologists ) N‑COUNT An ophthalmologist is a medical doctor who specializes in diseases and problems affecting people's eyes.
oph|thal|mol|ogy /ɒ fθælmɒ lədʒi/ N‑UNCOUNT Ophthalmology is branch of medicine concerned with people's eyes and the problems that affect them.
opi|ate /oʊ piət/ (opiates ) N‑COUNT An opiate is a drug that contains opium. Opiates are used to reduce pain or to help people to sleep.
opine /oʊpa I n/ (opines , opining , opined ) VERB To opine means to express your opinion. [FORMAL ] □ [V with quote] 'She's probably had a row with her boyfriend,' Charles opined. □ [V that] He opined that the navy would have to start again from the beginning. [Also V + on/about ]
opin|ion ◆◆◇ /əp I njən/ (opinions )
1 N‑COUNT [oft poss N , N that] Your opinion about something is what you think or believe about it. □ I wasn't asking for your opinion, Dick. □ He held the opinion that a government should think before introducing a tax. □ Most who expressed an opinion spoke favorably of Thomas.
2 N‑SING Your opinion of someone is your judgment of their character or ability. □ [+ of ] That improved Mrs Goole's already favourable opinion of him.
3 N‑UNCOUNT You can refer to the beliefs or views that people have as opinion . □ Some, I suppose, might even be in positions to influence opinion. □ [+ about ] There is a broad consensus of opinion about the policies which should be pursued.
4 N‑COUNT [usu sing] An opinion from an expert is the advice or judgment that they give you in the subject that they know a lot about. □ Severe, prolonged pain, especially at rest, needs a medical opinion.
5 → see also public opinion , second opinion
6 PHRASE You add expressions such as ' in my opinion ' or ' in their opinion ' to a statement in order to indicate that it is what you or someone else thinks, and is not necessarily a fact. □ Well, he's not making a very good job of it in my opinion.
7 PHRASE If someone is of the opinion that something is the case, that is what they believe. [FORMAL ] □ Frank is of the opinion that the 1934 yacht should have won.