Tatsama (Sanskrit: तत्सम IPA: [tɐtsɐmɐ], lit. 'same as that') are Sanskrit loanwords in modern Indo-Aryan languages like Assamese, Bengali, Marathi, Nepali, Odia, Hindi, Gujarati, and Sinhala and in Dravidian languages like Tamil, Kannada and Telugu. They generally belong to a higher and more erudite register than common words, many of which are (in modern Indo-Aryan languages) directly inherited from Old Indo-Aryan (tadbhava). The tatsama register can be compared to the use of loan words of Greek or Latin origin in English (e.g. hubris).

The origin of tatsama words (Bengali: তৎসম, romanized: tôtśômô) in Bengali is traced to 10th century Brahmin poets, who felt that the colloquial language (Old Bengali) was not suitable for their expressive needs. Another, more minor, wave of tatsama vocabulary entered the (Modern) Bengali language by Sanskrit scholars teaching at Fort William College in Kolkata at the start of the 19th century. Bengali's lexicon is now about 40% tatsama (with about 58% tadbhava vocabulary inherited from Old Indo-Aryan via the Prakrit languages such as Apabhramsha and Avahaṭṭha).^[1]

Early Odia dictionaries such as Gitabhidhana (17th Century), Sabda Tattva Abhidhana (1916), Purnachandra Odia Bhashakosha (1931) and Promoda Abhidan (1942) list Sanskrit Tatsama vocabulary.

They are derived from Sanskrit verbal roots with the addition of suffixes and known in Odia as "tatsama krudanta".

The way the tatsama entered the Sinhala language is comparable to what is found in Bengali language: they are scholarly borrowings of Sanskrit or Pali terms. Tatsama in Sinhala can be identified by their ending exclusively in -ya or -va,^{[citation needed]} whereas native Sinhala words tend to show a greater array of endings. Many scientific concepts make use of tatsama, for instance grahaņaya 'eclipse', but they are also found for more everyday concepts.^{[citation needed]}

For the most part, the western Indo-Aryan languages such as Punjabi, Sindhi, Hindko, and Saraiki do not use tatsama vocabulary. The majority of words in these languages are inherited from Prakrit or borrowed from Persian and Arabic. The notable exception in the group of western Indo-Aryan languages is Hindustani, which began with most of its borrowed vocabulary coming from Persian, and in recent history has incorporated a larger amount of learned borrowings from Sanskrit.^[2] Many of these, however, are borrowed indirectly from Bengali or Marathi,^[3] or given meanings based on English or Perso-Arabic derived words already in use in Hindustani.^[4][5] Any tatsama vocabulary occurring in Punjabi is borrowed from Hindi/Urdu,^[6] and likewise tatsama words in languages spoken further west are likely to be indirect loans of Hindi/Urdu words used in Punjabi. Very few of these are used in colloquial speech, and their use tends to be limited to formal settings or Hindu religious contexts.^[7]

Malayalam has many tatsama words, which are used in written and spoken language depending on register and dialect.

For example:

Sanskrit influenced the Telugu language for about 500 years. During 1000-1100 AD, Nannaya's Telugu in Mahabharata, Telugu in several inscriptions, Telugu in poetry reestablished its roots and dominated over the royal language, Sanskrit. Telugu absorbed the Tatsamas from Sanskrit.^[8]

Metrical poetry in Telugu ('Chandassu') uses meters such as Utpalamala, Champakamala, Mattebham, Sardoola, Sragdhara, Bhujangaprayata etc.. which are pure Sanskrit meters.

Telugu has many tatsama words, known as prakruti. The equivalent colloquial words are called vikrutis, meaning "distorted". Prakruti are used only as a medium of instruction in educational institutions, offices etc. Today, spoken Telugu contains both prakruthi and vikruthi words.

For example: