This is the step we all know and often resist. And sometimes resistance is a reasonable response. If you look at the context, the surrounding words, sometimes you can get a sense of what the word means. And even if you can’t, that context will help you choose the correct definition when you do look it up.
So the first thing to do is look at the setting of the unknown word – are there are clues to its meaning? Any synonyms or antonyms (words that seem to have a similar or opposite meaning)? Any examples that give you a sense of the new meaning? What about whether the word seems to be positive or negative? All of these things can provide helpful clues.
The next thing to do is look at the word itself and see if there are any parts of it you already know. If you know enough of the parts, you can make a reasonable guess and move on. For example, say you come across the word “bio-ethics” and have never seen it before. But you know “bio-” has to do with life and “ethics” has to do with moral principles. So bio-ethics must be ethical principles about life. Good enough to keep you moving forward in the text.
If the context and parts don’t give you enough to move forward and the word seems important, the next step is to look it up, either online or in a physical dictionary. If there is only one meaning, yay. If there are multiple meanings, go back to the context of the word and decide on the one that makes the most sense.
Last of all, write it down! Write down the new word and the most likely meaning in a dedicated space – your own personal dictionary. And most important, also write down the sentence in which it appeared. This will be a key tool in the final steps – learning the word well enough to actually use it.