sermon

UK: /ˈsɜː^rmən/ US: /ˈsɝmən/ ,(sûr′mən)

WordReference Random House Learner's Dictionary of American English © 2025

ser•mon /ˈsɜrmən/   n. [countable]

1. Religion a talk given for religious instruction.
2. any serious talk, esp. on morals:
   Don't give me a sermon on how to run my life!
3. a long, boring speech.

WordReference Random House Unabridged Dictionary of American English © 2025

ser•mon  (sûr′mən), n. 

1. Religion a discourse for the purpose of religious instruction or exhortation, esp. one based on a text of Scripture and delivered by a member of the clergy as part of a religious service.
2. any serious speech, discourse, or exhortation, esp. on a moral issue.
3. a long, tedious speech.

• Medieval Latin sermōn- (stem of sermō) speech from pulpit, Latin: discourse, equivalent. to ser- (base of serere to link up, organize) + -mōn- noun, nominal suffix
• Middle English 1150–1200

ser′mon•less, adj. 
Synonyms

• 2, 3. lecture.
• 3. harangue, tirade.

Collins Concise English Dictionary © HarperCollins Publishers::

sermon / ˈsɜːmən/ noun

1. an address of religious instruction or exhortation, often based on a passage from the Bible, esp one delivered during a church service
2. a written version of such an address
3. a serious speech, esp one administering reproof

Etymology: 12th Century: via Old French from Latin sermō discourse, probably from serere to join together