Letter: o
- opera house, Elizabethan theatre, Greek theatre, amphitheatre, arena, arena theatre, assembly hall, auditorium, cabaret, chapel, circle theatre, club, concert hall, convention hall, dance hall, exhibition hall
- opera score, arrangement, copy, draft, draught, draughtsman, draughty, edition, hymnal, libretto, music, music roll, notation, opera, part, score
- opera singer, alto, aria singer, baritone, bass, basso, blues singer, canary, cantor, caroller, chanter, coloratura soprano, comic bass, contralto, counter-tenor, crooner
- opera, Elizabethan theatre, Greek theatre, Passion play, amphitheatre, arena theatre, arrangement, artefact, audience success, auditorium, ballad opera, ballet, bomb, brainchild, broadcast drama, burlesque show
- operability, availability, effectiveness, efficiency, feasibility, manageability, manoeuvrability, maturity, practicability, practicality, use, usefulness, utility, viability
- operable, achievable, applicable, attainable, compliant, doable, effective, effectual, efficient, exploitable, feasible, fit, functional, in working order, manageable, manipulable
- operate on, act on, act upon, affect, bandage, bathe, care for, concentrate on, cure, diagnose, doctor, flux, focus on, give care to, heal, influence
- operate, act, angle, be caught short, be effective, be in action, be responsible for, be short, behave, belong, brew, bucket, cabal, carry on, carry out, carry through
- operatic overture, curtain raiser, descant, introduction, overture, prelude, vamp, voluntary
- operatic singing, bravura, coloratura, hum, humming, intonation, scat, scat singing, singing, song, vocalization, warbling, yodel
- operatic, Thespian, actor-proof, all-star, alto, ballet, balletic, baritone, bass, bravura, choral, cinematic, cinematographic, coloratura, dramatic, dramatical
- operating company, business, cartel, chamber of commerce, combine, company, concern, conglomerate, consortium, corporation, enterprise, firm, holding company, house, industry, partnership
- operating costs, budget, charge, cost, cost of living, expense, liabilities, overhead, swindle sheet, upkeep
- operating expense, budget, charge, cost, cost of living, expense, liabilities, overhead, swindle sheet
- operating room, X ray, blood bank, charity ward, clinic, consultation room, delivery room, dispensary, emergency, examining room, fever ward, hospital room, intensive care, isolation, laboratory, labour room
- operating, acting, active, at work, behavioural, functional, functioning, going, going on, in exercise, in force, in hand, in operation, in play, in practice, in process
- operation, accomplished fact, accomplishment, achievement, act, acting, action, activism, activity, adventure, affair, amphibious operations, amputation, anastomotic operation, appliance, application
- operational purpose, duty, function, office, operation, purpose, role, use, work
- operational, acting, active, agentive, at work, behavioural, effective, effectual, efficacious, efficient, functional, functioning, go, going, going on, in exercise
- operations research, approach, arrangement, attack, blueprint, calculation, conception, contrivance, design, device, disposition, enterprise, foresight, forethought, game, guideline
- operations, act, acting, action, activism, activity, behaviour, campaign, doing, dry run, employment, exercise, function, functioning, joint operation, logistics
- operative, FBI, Federal, Sherlock Holmes, accessible, active, actor, agent, alive, architect, artisan, author, authoritative, cloak-and-dagger operative, cogent, conductor
- operator gene, DNA, gene, genotype, heredity
- operator, Machiavellian, activist, actor, administrator, adventurer, agent, architect, author, ball of fire, beaver, behind-the-scenes operator, big operator, big wheel, big-time operator, busy bee
- operetta, ballad opera, ballet, chorus show, comedy ballet, comic opera, dance drama, grand opera, light opera, lyric drama, minstrel, minstrel show, music drama, musical, musical comedy, musical stage
- ophthalmic, eyeball, ocular, optic, visible, visual
- ophthalmologist, anaesthesiologist, cardiologist, chiropodist, dermatologist, eye doctor, eye-ear-nose-throat specialist, gerontologist, gynaecologist, immunologist, neurologist, obstetrician, oculist, orthopaedics, paediatrician, pathologist
- opiate, Mickey Finn, Nembutal, accept, alcohol, anaesthetic, analgesic, anodyne, barb, barbiturate, barbiturate pill, believe, black stuff, blue, blue angel, blue devil
- opine, account, account as, adjudge, adjudicate, allow, allude to, assume, be afraid, be judicious, believe, blurt, blurt out, call attention to, comment, conceive
- opinion poll, canvass, inquiry, poll, questionnaire, survey
