parasol, sombrilla, paraguas
From the Picture of the day: chick with an umbrella
Now, not everybody used the word correctly.
Paraguas: literally: para agua, for water
So this one is not used on the beach, where it is supposed to be sunny ![]()
Parasol: Para el sol, for the sun.
However, when I think of this word, I think of something a Victorian lady would carry in her days so as not go get a tan ![]()
We do not use this world in Spain for a sunshade.
Over here we say
Sombrilla : sombra sombrilla , little shade (some shade)

4 Answers
Es bueno tener esta información, no lo había pensado. ![]()
I agree that technically there's a distinction between sombrilla/parasol, and paraguas. Nevertheless, I find that in much of Latin America, the terms are used interchangeably.
I also agree that "parasol" is rarely used anywhere.
Nosotros usamos "paraguas" cuando llueve. Umbrella.
Cuando vamos a la playa usamos "sombrilla".
No usamos la palabra "parasol".
Hello!
These two links from wordreference might be pertinent to this subject. They are discussed by users from Spain & the Americas.
Hope this helps.
Regards!