Entity Extraction: what is it, and how does it work?

Have you ever wondered how the content of a web page is extracted from its HTML code? Or you’ve seen an article that mentions entities, such as people or places, and wondered what they are. If you’ve worked with data, you’re probably familiar with entity extraction (EE). It’s a process that involves finding and identifying entities in free text. This article will discuss an entity and how you can use it to make sense of unstructured content like blog posts, emails, or tweets.

What is entity extraction?

EE is a very powerful feature of search. It can help you find new information and discover patterns in your data. It is particularly useful when searching unstructured text because it enables you to understand what information is most relevant to whatever topic you are searching for.

Extracting entities is a fundamental aspect of NLP. It’s essential to extract relevant text data from any natural language processing system. EE engines identify entities and their corresponding types.

What can entity extraction do for you?

EE can be used for a variety of purposes. It is a way to find the right information, people, products, and locations. For example:

  • You want to know where your customers are located; you can use EE to identify addresses and cities in their emails.
  • You want to build an email marketing campaign; you can use EE to identify which companies have purchased from you in the past so that you can contact them about another product or service offering.
  • You want an overview of what types of food your social media followers like most; you can use EE on their tweets and posts from Instagram or Facebook (or any other social media platform) and segment them accordingly.

What are the different kinds of entities?

You can define an entity in several ways. The most basic is to describe the type of thing your entity represents. For example, a person or an organization; is the most straightforward entity you can extract from the text. Other kinds include location (e.g., “United States”), event (“World War II”), product or service (“Ford Mustang”), activity (“driving”) and time (“1:00 PM”).

The next step is determining what information about each entity should be extracted from the text to be useful for your application’s use case. Since entities are often used as reference points for other types of information—for example, people’s names often appear in news articles—you may want them to appear in full form when inserted into another dataset, such as a database table or CSV file containing other data related to that article (such as citations). In other cases, extracting just one aspect will suffice (for example, extracting only someone’s name).

How does EE work?

EE is a type of natural language processing (NLP) that aims to identify and extract meaning from text. In particular, it can be used to find and extract people, places, events and organizations.

EE relies on machine learning models that have been trained using labeled data. The training data consists of example texts containing both entities (the entity being identified) and non-entities (everything else). To identify whether something is an entity, you need a way to measure how likely it is that this word will be an entity. This is where classification comes into play: you give each example a label indicating whether it contains an entity and train your model based on these labels.


In conclusion, EE is an important component of many applications. It can be used to enhance the quality of search results, personalize recommendations and advertisements, or even automatically generate product descriptions. The main challenge for engineers working on this technology is extracting entities from unstructured text data such as tweets and blog posts.