computer science

Search engine

Search engine is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Search engine rather than just read about it. In short: The term search engine refers to a search application that provides links to web pages and other relevant information on the Web (or the Internet in general) in response to a user's query. Users submit their queries through a web browser or a mobile app, and the results page generally displays a collection of hyperlinks together with brief descriptions and relevant images.

Key takeaways

Search engine belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Search engine to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Search engine from memory before moving on to harder problems.

Reference excerpt

The term search engine refers to a search application that provides links to web pages and other relevant information on the Web (or the Internet in general) in response to a user's query. Users submit their queries through a web browser or a mobile app, and the results page generally displays a collection of hyperlinks together with brief descriptions and relevant images. Users also have the option of limiting a search to specific types of results, such as images, videos, or news. For a search provider, its engine is part of a distributed computing system that can encompass many data centers throughout the world. The speed and accuracy of an engine's response to a query are based on a complex system of indexing that is continuously updated by automated web crawlers. This can include data mining the files and databases stored on web servers, although some content is not accessible to crawlers. There have been many search engines since the dawn of the Web in the 1990s; Google Search became the dominant one in the 2000s and has remained so. As of May 2025, according to StatCounter, Google held approximately 89–90 % of the worldwide search share, with competitors trailing far behind: Bing (~4 %), Yandex (~2.5 %), Yahoo! (~1.3 %), DuckDuckGo (~0.8 %), and Baidu (~0.7 %). May 2025 marked the first time in over a decade that Google's share has fallen below the 90% threshold. Because of its market share, the discipline of websites improving their visibility in search results, known as marketing and optimization, has historically largely focused on Google.

History

Pre-1990s In 1945, Vannevar Bush described an information retrieval system that would allow a user to access a great expanse of information, all at a single desk, which he called a memex. He described this system in an article titled "As We May Think" in The Atlantic Monthly. The memex was intended to give a user the capability to overcome the ever-increasing difficulty of locating information in ever-growing centralized indices of scientific work. Vannevar Bush envisioned libraries of research with connected annotations, which are similar to modern hyperlinks. Link analysis eventually became a crucial component of search engines through algorithms such as Hyper Search and PageRank.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Search engine

Start with the simplest possible case. Write down what Search engine claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Search engine before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Search engine ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Search engine

In research: Search engine appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Search engine in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Search engine is common in secondary-school and first-year university syllabi. It links to neighbouring topics Canadian inventions, History of the Internet, Internet properties established in 1993, so understanding it makes those chapters shorter.
In everyday life: Look for Search engine outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Search engine in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Search engine means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Search engine out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Search engine in simple terms?

Why does Search engine matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Search engine?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Search engine.