Risa vs. carcajada

In the Spanish language, both 'risa' and 'carcajada' refer to the act of laughing. However, there is a subtle difference in intensity and the context in which these words are used.

Risa

It refers to general laughter, without specifying its intensity. The term can be used in multiple contexts, from a gentle chuckle to laughing out loud.
No podía contener la risa cuando vio el disfraz que llevaba su amiga.
(She couldn't hold back her laughter when she saw the costume her friend was wearing.)
La risa es la mejor medicina.
(Laughter is the best medicine.)
Sacó una risa nerviosa al escuchar la noticia.
(He let out a nervous laugh upon hearing the news.)

Carcajada

The term 'carcajada' indicates loud, explosive laughter. It connotes a higher intensity of laughter usually associated with immense joy or amusement.
El chiste fue tan gracioso que soltó una carcajada.
(The joke was so funny that he let out a roar of laughter.)
La sala entera estalló en carcajadas después de su comentario cómico.
(The entire room burst into belly laughs after his comedic comment.)
No pude evitar una carcajada al ver cómo bailaba el perro en el video.
(I couldn't help but burst out laughing at how the dog was dancing in the video.)

Summary

'Risa' and 'carcajada' both describe laughter in Spanish but have contrast in intensity. While 'risa' is used broadly to denote any kind of laughter, 'carcajada' specifically refers to loud or hearty laughter.