Online Encyclopedias

Compiled by Jayaram V

Summary:This page offers a curated collection of online encyclopedias covering a wide range of subjects, including biology, environment, medicine, arts, culture, history, languages, computing, mythology, philosophy, physics, religion, and general knowledge. It provides convenient access to specialized reference works, research tools, and educational resources. While the links are regularly updated, availability may vary, and users are encouraged to verify each site’s credibility. The page serves as a helpful gateway for students, researchers, and lifelong learners.

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A brief history of Encyclopedias

The word encyclopedia comes from a Greek phrase meaning “general education” or “complete knowledge.” In the 1400s, copyists mistakenly combined the two Greek words into one, and that new form became the Latin encyclopaedia, which English later adopted. Today, spelling varies: encyclopedia is common in American English, while encyclopaedia is traditional in British English (though encyclopedia is increasingly used there too).

Encyclopedias have existed for about 2,000 years, and even older glossaries are sometimes described as encyclopedias. In ancient Rome, Marcus Terentius Varro wrote Nine Books of Disciplines, which influenced later writers. The oldest major encyclopedia that still survives is Pliny the Elder’s Naturalis Historia (1st century AD). It covers topics like nature, medicine, geography, architecture, and geology, and it became widely copied and read. It is still an important source for information about the Roman world.

Early Christian and medieval scholars also created encyclopedias. Cassiodorus wrote Institutiones (6th century), with one part on Christian teaching and another on the seven liberal arts. Around 630, Isidore of Seville wrote Etymologiae, a major medieval encyclopedia in 20 volumes. It preserved many quotations from older works that might otherwise have been lost. Later encyclopedias included Hortus deliciarum (12th century) by Herrad of Landsberg and large works such as Vincent of Beauvais’s Speculum Majus (13th century).

During the Renaissance, printing made encyclopedias easier to produce and share. In 1493, the Nuremberg Chronicle was published with many illustrations of people, events, and places. It is one of the best-known early printed books and an early example of combining text and images effectively.

In the 1500s, some humanists misread ancient texts and combined the Greek words for “general education” into a single term. This helped popularize the word encyclopaedia. In 1646, English writer and physician Sir Thomas Browne used the term in the introduction to Pseudodoxia Epidemica, and he organized knowledge using a “scale of creation,” moving from minerals up to the cosmos.

Modern, general-purpose printed encyclopedias developed before and during the 1700s. Key examples include Chambers’ Cyclopædia (1728), Diderot and d’Alembert’s Encyclopédie (starting in 1751), Encyclopædia Britannica, and Germany’s Conversations-Lexikon. These works aimed to cover many subjects in depth and organize information in a clear, systematic way.

In the Byzantine world, encyclopedias collected information from both ancient Greece and later Byzantine sources. One early example was the Bibliotheca by Photius (9th century). Another major work was the Suda (10th century), a large Greek encyclopedia with about 30,000 entries drawn from many older sources, including some works that no longer exist.

Arabic and Persian

In the medieval Islamic world, scholars produced many large works that collected and organized knowledge. One example is the Encyclopedia of the Brethren of Purity, created in Basra around the year 960.

Other important works include al-Razi’s writings on science, al-Kindi’s many books, and Ibn Sina’s medical encyclopedia, which was used as a reference for centuries. Historians such as al-Tabari, al-Masudi, and Ibn Khaldun also shaped how knowledge was recorded. Ibn Khaldun’s Muqaddimah, for example, warns readers to be careful when trusting written sources. Scholars emphasized checking sources and verifying reports, which influenced later research and editing practices.

In Iran, recent encyclopedia projects include the Encyclopaedia of the World of Islam (10 volumes) and the Encyclopaedia of Contemporary Islam (four volumes, about 1,200 entries). Other examples include encyclopedias focused on Imam Ali, Qur’anic studies, and Lady Fatima, published by the Islamic Research Institute for Culture and Thought (IICT).

India

Siribhoovalaya (dated roughly from 800 AD to the 1400s) is a Kannada work by the Jain monk Kumudendu Muni. It organizes information using numbers rather than an alphabet. It includes philosophy and also covers subjects such as mathematics, chemistry, physics, astronomy, medicine, history, and travel.

The work contains about 600,000 verses across 26 chapters, making it far longer than the Mahabharata.

Varāhamihira’s Brihat Samhita (6th century) is another encyclopedic work. It covers astrology as well as topics like weather and rainfall, animals, perfumes, medicine, and architecture.

China

China produced several massive encyclopedias, especially from the Song dynasty onward. The “Four Great Books of Song” were compiled in the 11th century. Later, the Yongle Encyclopedia was completed in 1408 under the Ming dynasty. With almost 23,000 manuscript volumes, it was the largest encyclopedia in history until modern times.

In the Qing dynasty, the Qianlong Emperor supported a huge collection called the Complete Library of the Four Treasuries, which gathered millions of pages of writing. Encyclopedic works also appeared in Japan from the 9th century, sometimes influenced by Chinese models.

Notable Chinese encyclopedic writers include Shen Kuo, who wrote Dream Pool Essays (1088), Wang Zhen, who wrote Nong Shu (1313), and Song Yingxing, who wrote Tiangong Kaiwu (1637).

Addtional Information

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The Early Christian Encyclopedias

1. Institutiones (560 CE) of Cassiodorus'.
2. Etymologiae (636) of St. Isidore of Seville's .
3. Bibliotheca by the Patriarch Photius (9th century) which is earliest Byzantine work that qualifies as an encyclopedia
4. De Proprietatibus Rerum (1240) of Bartholomeus de Glanvilla
5. Speculum Majus (1260) of Vincent of Beauvais, which had over 3 million words.

The early Muslim encyclopedias are:

1. Encyclopedia of the Brethren of Purity.
2. Abu Bakr al-Razi's encyclopedia of science,
3. The Mutazilite Al-Kindi's prolific output of 270 books,
4. Ibn Sina's medical encyclopedia,
5. Works of universal history (or sociology) from Asharites,
6. Tabari's History of the Prophets and Kings,
7. Muqadimmah which contains cautions regarding trust in written records that remain wholly applicable today.

The early Chinese Encyclopedias

1. The Four Great Books of Song, compiled in the 11th century during the early Song Dynasty (960-1279),
2. The last encyclopedia of the four, the Prime Tortoise of the Record Bureau, with 9.4 million Chinese characters in 1000 written volumes.
3. The Dream Pool Essays of Shen Kuo (1031-1095)
4. The Nong Shu of Wang Zhen (1290-1333)
5. The written Tiangong Kaiwu of Song Yingxing (1587-1666).
6. Yongle Encyclopedia, one of the largest encyclopedias in history.

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