1. Common uses
"Effect" is most commonly used as a noun and refers to something that happens because of some action or event. A good synonym is "result." For example, pretend that you are watching a fireworks display, and one rocket makes a really big boom. The person next to you, deafened by the blast, turns to you and shouts, "That was a really great effect." That person is referring to the blast that occurred when the rocket exploded, i.e., the result of the explosion.
"Affect" is most commonly used as a verb and refers to the action of influencing something else. In fact, "influence" (the verb) is a good synonym. For example, when the person just mentioned has finished shouting about the effect, you might respond, "Yeah, it must have affected your hearing."
Here are a few more samples:
1. What will be the effect of winking at her? Will winking affect her opinion of me?
2. When she smiles at me, my whole day is affected. It's a strange effect.
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2. Less common uses
""Effect" is sometimes used as a verb, though we don't like this use. It is too "new-speaky" for us, like using "dialogue" as a verb, which it isn't. When "effect" is being used as a verb, it refers to the action of causing something to occur. An example of this is: "My wink effected a change in her attitude about me."
"Affect" can be correctly used as a noun. As a noun, this refers to emotions or an emotional response. You will find many examples of this in psychology documents. An example is: "Her affect was strange when I winked at her."
3. Quick Summary
Effect: Noun, means result
Affect: Verb, means influence; Noun, means emotional response
