Embedding
An embedding is a list of numbers that represents the meaning of a word, sentence, image or document, so that similar things get similar numbers. It lets software find related content by meaning rather than by exact words.
In one line, for a 12-year-old
An embedding is a secret number-address for an idea, so ideas that mean the same thing live close together.
An example
Searching a help centre for "can't log in" finds the article titled "Password reset", because their embeddings are close.
Why it matters to people
Embeddings make search and recommendations smarter, but they can also encode stereotypes found in the text they were built from.