Tesis vs. disertación

In the Spanish language, 'tesis' and 'disertación' are terms often used in academic contexts to refer to extensive research or scholarly work, primarily for the purpose of obtaining a university degree. Although seemingly interchangeable, these words carry subtle differences in usage and connotation that are important to understand for anyone involved in academic writing or the educational system in Spanish-speaking countries.

Tesis

The word 'tesis' is used to denote a document submitted in support of candidacy for an academic degree or professional qualification that presents the author's research and findings.
Ella defendió su tesis de doctorado ayer.
(She defended her doctoral thesis yesterday.)
La tesis sobre cambio climático ganó un premio internacional.
(The thesis on climate change won an international award.)
Mi tesis de maestría fue sobre la literatura renacentista.
(My master's thesis was on Renaissance literature.)

Disertación

The term 'disertación' refers to a detailed discourse or lecture on a subject, often part of a university degree, but not exclusively associated with the final thesis or dissertation. It can also mean any scholarly exposition that elaborates on a specific topic.
El estudiante dio una disertación sobre las teorías económicas modernas.
(The student gave a dissertation on modern economic theories.)
Para la clase de historia, preparé una disertación sobre la Revolución Francesa.
(For history class, I prepared a dissertation on the French Revolution.)
Su disertación explicó los principios básicos de la física cuántica de manera entendible.
(His lecture explained the basic principles of quantum physics in an understandable way.)

Summary

While both 'tesis' and 'disertación' are integral to the sphere of academic research and study in Spanish-speaking contexts, they represent different aspects of it. 'Tesis' primarily refers to the substantial research paper required for degrees such as Master's and Ph.D. that embodies original research or substantive findings. On the other hand, 'disertación' can mean either a detailed written treatment of a subject (similar to a thesis) or an oral presentation/lecture, emphasizing the different formats through which knowledge is disseminated academically.