Learner's definition of ADVERTISEMENT
1 [count] : something (such as a short film or a written notice) that is shown or presented to the public to help sell a product or to make an announcement
— often + for
The advertisement will appear in three magazines.
He learned about the job from an advertisement in the newspaper.
a television/radio advertisement
— called also ad, "British"advert
2 [count] : a person or thing that shows how good or effective something is — + for 3 [noncount] : the act or process of advertising