(n) (abbr) medical operation
(P)
(n) opera (ita:)
(P)
(n) opaque
(n) (comp) opcode
(n) Organization of Petroleum Exporting Countries (Organisation)
OPEC
(n) opera house
(n) operon
(n) (abbr) system operator
sysop
(n) (abbr) buying operation
(n) (abbr) selling operation
(n) (abbr) operational amplifier
(n) (comp) operation code
op-code
(n) operant
(n) (comp) operand
(n) opera singer
(n) operator
(n) operetta (ita:)
(P)
(n) operon theory (Jacob & Monod, 1961)
(n) Cassiopeia
(n) opera glasses
(n) opera seria (ita:)
(n) opera house
(n) opera hat
(n) opera bag
(n) operator
(P)
(n) soap opera
(n) light opera
(n) comic opera (fre: opera-comique)
(n) opera buffa (ita:)
(n) operation
(P)