The CDC modified the definition of "vaccination" on the CDC website, replacing the word "immunity" with "protection"
Previous definitions:
https://web.archive.org/web/20210826113846/https://www.cdc.gov/vaccines/vac-gen/imz-basics.htm
Current definitions:
https://www.cdc.gov/vaccines/vac-gen/imz-basics.htm
The change was simply to avoid a common misunderstanding about the meaning of having "immunity" and the state of being "immune", which may imply 100% protection. All vaccines convey immunity, but no vaccine is 100% effective, so it may be misleading to imply that a vaccine makes you "immune".
All COVID-19 vaccines are "vaccines" whether you use the old definition or the new one.
According to the CDC, a vaccine is "a preparation that is used to stimulate the body’s immune response against diseases. Vaccines are usually administered through needle injections, but some can be administered by mouth or sprayed into the nose."
Fact check: Missing context in claim that Merriam-Webster changed 'vaccine' definition (2021-11-30)
https://www.usatoday.com/story/news/factcheck/2021/11/30/fact-check-merriam-webster-changed-vaccine-definition-accuracy/6354415001/
Why did CDC change its definition for 'vaccine'? Agency explains move as skeptics lurk (2021-09-27)
https://www.miamiherald.com/news/coronavirus/article254111268.html
Immunization: The Basics (CDC, 2021-09-01)
https://www.cdc.gov/vaccines/vac-gen/imz-basics.htm