15-Letter Words Ending in ER

There are 20 15-letter words that end in ER. 3 are common words, such as CINEMATOGRAPHER and HISTORIOGRAPHER. A rarer one is ULTRAMARATHONER. 5 words contain a doubled letter.

Full list 20

cinematographerhistoriographerphototypesetterautotransformermalpractitionermicromillimeterphotomultiplierradiomicrometertelethermometerthermobarometerultramicrometerchromatographercounterattackercounterreformerdiastereoisomermicrophotometerphotosensitizerphytogeographertransmissometerultramarathoner

About this list

Words
20 (3 common words)
Common example
cinematographer
Rare example
ultramarathoner
Doubled letters
5
Ending in S
0

Questions

How many 15-letter words ending in er are there?

20. 3 of them are common words.

What is a common example?

CINEMATOGRAPHER is among the common words in this set.