demostrar

Forms

demostrar (first-person singular present demuestro, first-person singular preterite demostré, past participle demostrado)^[1] Old Spanish texts also have the Latinising spelling demonstrar, which Nebrija still used.^[2][3] Old Castilian had the reduced forms demosar and denosar.^[4]

Etymology

It is inherited from Latin dēmōnstrō (“to point out, indicate, describe”).^[3][5][6][1] Corominas notes that the verb sometimes has a semi-learned look, as in Nebrija's spelling demonstrar.^[3]

It is formed from Latin dē- + mōnstrō (“to show”).^[1][7] The simple verb comes from mōnstrum (“portent, sign”), which Wiktionary analyses as moneō (“to remind, warn”) with an instrument suffix.^[1] De Vaan derives the noun from a suffixed form built on the stem of the verb, which goes back to Proto-Indo-European *mon-eie- (“to make think of, remind”).^[8]

Spanish shares the verb with the other Romance languages: Portuguese demonstrar, Catalan demostrar, French démontrer and Italian dimostrare.^{[9][10][11][12]}

Earliest recorded meaning

The Cantar de mio Cid (c. 1140, known from a 14th-century copy) has the verb twice, in the sense “to show”: demuéstranles amor “they show them love” (v. 2703), said of the Infantes de Carrión with their wives, and bien gelo demostraron a todos “they showed it clearly to everyone” (v. 3606).^[13][14][15]

Semantic evolution

In the 13th century the verb already covered “to show, reveal”, “to prove” and “to teach”: the Lapidario of Alfonso X says that a stone demuestra the heat shut up inside it, and that a matter se demuestra by three divisions, and the hunting treatise Moamín uses the reflexive for birds that learn to enter low places.^[16] Corominas notes that in the old language mostrar itself could mean “to teach”, and the Academy still listed “to teach” as an old sense of demostrar in 1817.^[3][17]

Nebrija gives demostrar con el dedo “to point out with the finger” for Latin indico.^[18] Covarrubias defines the verb as “to declare, make manifest”.^[19] From 1817 the Academy put the sense “to prove by principles” first, and by 1899 it added a sense in logic: to show that a particular truth is contained in a universal one.^[17][20] The DLE keeps these senses;^[6][21] Moliner adds the practical sense of showing how something is done.^[6][21]

The learned noun demostración replaced the older demuestra, which Nebrija still recorded, and demostramiento.^[3]

Timeline

• c. 1140 – the Cantar de mio Cid uses demostrar for “to show”.^[13][5]
• 1211 – first year of the verb in the Old Spanish Textual Archive.^[22]
• 1250–1279 – Alfonso X's Lapidario uses it for “to show” and “to prove”.^[16]
• c. 1495 – Nebrija gives demostrar con el dedo for Latin indico.^[18]
• 1570 – first record of the noun demostración.^[5]
• 1611 – Covarrubias defines it as “to declare, make manifest”.^[19]
• 1615 – first record from the Americas, in Quito.^[23]
• 1616 – first record of demostrativo.^[5]
• 1817 – the Academy lists “to prove by principles” first and “to teach” as an old sense.^[17]
• 1899 – the Academy gives the Latin etymology and adds the sense in logic.^[20]

Meanings

Verb

1. To show, make manifest or declare something: Su silencio demostraba el miedo que tenía.^[6][24]
2. To prove something with evidence or reasoning: demostrar una hipótesis.^[6][21][1]
3. To show or explain in practice how something works or is done; to demonstrate.^[6][21][24]
4. (philosophy) To show that a particular truth is contained in a universal one known with certainty.^[6]

Word family

• demostrable
• demostración
• demostrador
• demostrativo

Related words

• mostrador
• mostrar
• mostrario
• muestrario
• muestra
• monstruo
• Latin dēmōnstrō
• Portuguese demonstrar

Usage notes

The verb is irregular like contar: the stressed stem has ue (demuestro, demuestran).^[25][1]

References

1. ^ a b c d e f g Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ Diccionario del Español Medieval electrónico (DEMel), data publication 2026 (CC BY-SA), Universität Rostock, p. s.v. demostrar
3. ^ a b c d e Corominas, Joan; Pascual, José A. (1980–1991), Diccionario crítico etimológico castellano e hispánico, 6 vols., Madrid: Gredos, p. 4, 164
4. ^ García de Diego, Vicente (1985), Diccionario etimológico español e hispánico, 2nd ed., Madrid: Espasa-Calpe (1st ed. 1954), p. 2179
5. ^ a b c d Corominas, Joan (1973), Breve diccionario etimológico de la lengua castellana, 3rd ed., Madrid: Gredos, p. s.v. mostrar
6. ^ a b c d e f g Real Academia Española; Asociación de Academias de la Lengua Española (2014–), Diccionario de la lengua española, 23rd ed., online version 23.8, https://dle.rae.es, p. s.v. demostrar
7. ^ Glare, P. G. W., ed. (2012), Oxford Latin Dictionary, 2nd ed., Oxford: Oxford University Press
8. ^ de Vaan, Michiel (2008), Etymological Dictionary of Latin and the other Italic Languages, Leiden Indo-European Etymological Dictionary Series 7, Leiden; Boston: Brill
9. ^ Segura Munguía, Santiago (2001), Nuevo diccionario etimológico latín-español y de las voces derivadas, Bilbao: Universidad de Deusto, p. 203
10. ^ Cunha, Antônio Geraldo da (2010), Dicionário etimológico da língua portuguesa, 4th ed., Rio de Janeiro: Lexikon, p. 1110
11. ^ Alcover, Antoni M.; Moll, Francesc de B. (1930–1962), Diccionari català-valencià-balear, 10 vols., Palma de Mallorca: Moll, p. s.v. demostrar
12. ^ Rey, Alain, ed. (1992), Dictionnaire historique de la langue française, Paris: Le Robert, p. s.v. démontrer
13. ^ a b Menéndez Pidal, Ramón (1908–1911), Cantar de Mio Cid: texto, gramática y vocabulario, 3 vols., Madrid: Bailly-Baillière, p. s.v. demostrar
14. ^ Real Academia Española (2013–), Corpus del Diccionario histórico de la lengua española (CDH), version 3.1, https://apps.rae.es/CNDHE, p. s.v. demostrar
15. ^ Boggs, R. S.; Kasten, Lloyd; Keniston, Hayward; Richardson, H. B. (1946), Tentative Dictionary of Medieval Spanish, 2 vols., Chapel Hill, N.C., p. 169
16. ^ a b Kasten, Lloyd A.; Nitti, John J.; Gago Jover, Francisco (2002–), Diccionario de la prosa castellana del Rey Alfonso X, New York: Hispanic Seminary of Medieval Studies (electronic edition 2024), p. s.v. demostrar
17. ^ a b c Real Academia Española (1817), Diccionario de la lengua castellana, 5th ed., Madrid: Imprenta Real, p. 284
18. ^ a b Nebrija, Antonio de (1513), Vocabulario español-latino, Salamanca, ed. Marina Vidal Díez (2007), Biblioteca Virtual Miguel de Cervantes, p. 329
19. ^ a b Covarrubias Orozco, Sebastián de (1611), Tesoro de la lengua castellana o española, Madrid: Luis Sánchez (Biblioteca Wordkers transcription, CC BY 4.0), p. 645
20. ^ a b Real Academia Española (1899), Diccionario de la lengua castellana, 13th ed., Madrid: Imprenta de los Sres. Hernando y Compañía, p. 321
21. ^ a b c d Moliner, María (2007), Diccionario de uso del español, 3rd ed., Madrid: Gredos, p. s.v. demostrar
22. ^ Hispanic Seminary of Medieval Studies (2026), Old Spanish Textual Archive (OSTA): semi-paleographic transcriptions of Old Spanish texts, ed. Francisco Gago Jover et al., https://www.hispanicseminary.org, p. s.v. demostrar
23. ^ Boyd-Bowman, Peter (2003), Léxico hispanoamericano 1493–1993, ed. Ray Harris-Northall and John J. Nitti, New York: Hispanic Seminary of Medieval Studies, p. s.v. demonstrar
24. ^ a b Battaner Arias, Paz (dir.) (2017), Diccionario general de la lengua española VOX, Barcelona: Larousse Editorial, p. s.v. demostrar
25. ^ Domínguez, Ramón Joaquín (1846–1847), Diccionario nacional o gran diccionario clásico de la lengua española, 2 vols., Madrid: Establecimiento Léxico-Tipográfico de R. J. Domínguez, p. 552