Other than sí, the word for yes, claro is probably the word most commonly used in Spanish for expressing agreement, either with something someone has said or with a statement expressed earlier by the speaker. As an intensifier, claro can be translated in a variety of ways, depending on the context.
Common translations include of course, evidently, obviously and yes. In such usages claro usually functions as a sentence adverb or an interjection. Here are some examples of its use:
Claro que no es bueno. (Clearly it's no good.)
Claro que no todo es un lecho de rosas. (Obviously not everything is a bed of roses.)
Sí, claro, quiero saber dónde estás, cómo estas. (Yes, of course, I want to know where you are, how you are.)
¿Me reconoces? ¡Claro que sí! ("Do you recognize me?" "Of course!")
¡Claro que no puedes! (Of course you can't!)
Claro que tienes pruebas. (Surely you have proof.)
¡Claro que no! (Of course not!)
¿Salimos? ¡Claro! (Are we leaving? Sure!)
Sabemos lo que sabemos, claro. (We know what we know, evidently.)
Additionally, as an adjective, claro has a variety of meanings including light in color, clear, evident, weak or thin (in the sense of being watered down), and frank.
In a nutshell, Spanish claro can be understood to be a term denoting some kind of assertiveness, a certainty. As in, "This will certainly happen," or, "Of course, this will happen." Taking this concept further, we can assume this certainty to be clearly definite which gives a visual hint to remember the word: Clearly. Clearly sounds similar to claro and can thus be used as a mental hook to remember the sense and meaning of this Spanish word!