13-Letter Words Starting With OP

There are 20 13-letter words that start with OP. 6 are common words, such as OPERATIONALLY and OPHTHALMOLOGY. A rarer one is OPTIONALITIES. In this set, T is the most frequent open letter (18 words). 8 words contain a doubled letter.

Full list 20

operationallyophthalmologyopportunisticopportunitiesopprobriouslyoptimizationsopportunenessopenabilitiesopenheartedlyopenmouthedlyoperabilitiesoperationismsoperationistsoperativenessoperosenessesopinionatedlyopisthobranchoppositionistoptimisationsoptionalities

About this list

Words
20 (6 common words)
Common example
operationally
Rare example
optionalities
Doubled letters
8
Ending in S
11
Most frequent letter
T (18)

Questions

How many 13-letter words starting with op are there?

20. 6 of them are common words.

What is a common example?

OPERATIONALLY is among the common words in this set.