Countable Nouns Starting with OP and Containing ER

Browse 39 valid English countable nouns starting with OP and containing ER, from Operation, Operator, Opera, Opener, Operative, Optimizer and Operetta to rarer terms. Check definitions and spelling below, or visit our noun grammar guide to review singular and plural count rules.

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Starts with OPA
1 words
opacifier
Starts with OPE20 words
operation
operator
opera
opener
operative
operetta
operand
operant
operon
operculum
operagoer
operatorship
opercular
operationalist
operativity
operationist
operettist
operosity
opercule
operatrix
Starts with OPH8 words
ophthalmometer
ophthalmodynamometer
ophthalmostatometer
ophthalmothermometer
ophiolater
ophthalmotonometer
ophthalmotropometer
ophthalmodiastimeter
Starts with OPI
2 words
opisometer
opificer
Starts with OPP3 words
opposer
oppugner
oppigneration
Starts with OPS
1 words
opsiometer
Starts with OPT4 words
optimizer
opter
optocoupler
optometer

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