I consider the OED, or Oxford English Dictionary, to be the Bible of dictionaries. One can never be too sure about a word and its meaning.
Now the dictionary is useful for what, you ask. Finding meaning? Sure. Anything else? Of course. Finding the meaning of a word is not the only reason you should use a dictionary. A dictionary can help build your vocabulary, speak English more fluently, or frame your sentences, which in turn, enhances your writing skills and builds your confidence when you’re writing.
For instance, I was recently informed by a co-worker that nauseous is inappropriately used to describe to someone that you’re suffering from nausea. Rather, you should simply say, “I’m feeling nauseated.” Naturally, I questioned this usage and looked to the OED for guidance. Sure enough, it hasn’t failed me yet.
Nauseous, like nauseated, is an adjective. However, it is used to indicate an inclination toward feeling nauseated as opposed to actually feeling sick. Nauseated means that you’re actually experiencing nausea.
Here’s an easy example to remember: amusement park rides make you nauseous; being hung over makes you nauseated.
It’s like telling someone they’re exceptionally gorgeous. You wouldn’t say that unless you thought their beauty to be especially rare or unique. On the same note, you wouldn’t tell someone you’re nauseous when you haven’t even begun to feel nauseated.