Countable Nouns That Start with OP and End with ION

Explore 12 verified English countable nouns starting with OP and ending with ION, including Operation, Opinion, Option, Opposition, Optimization, Oppression and Opsonization. Sort these count nouns with singular and plural forms by word length for ESL grammar practice, determiner usage, and plural spelling below, or review singular and plural count rules in our noun grammar guide.

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Starts with OPA
1 words
opacification
Starts with OPE
1 words
operation
Starts with OPI
1 words
opinion
Starts with OPP
5 words
opposition
oppression
oppilation
oppignoration
oppigneration
Starts with OPS
2 words
opsonization
opsonification
Starts with OPT
2 words
option
optimization

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