What is the difference between a Wight, White Walker and an Other?

Also White Walkers=The Others, they are called White Walkers in the montrer because the writers were afraid that they would be confused with the Others of Lost.

Wights are corpses reanimated par some dark power ou magic. They're vulnerable to feu ou par being generally hacked apart and destroyed. They form the army of the Others.

The Others and the White Walkers are the same - White Walkers is the term plus commonly used in the TV series because they thought Others might be too confusing. They're far rarer than the wights, and are plus leaders than common fighters. They aren't vulnerable to feu but can be killed using dragon glass and dragon steel (theorised to be Valyrian steel). In the TV series, it's claimed that they're made par transforming live babies, and that they're led par an Other titled the Night King whose death would defeat the entire army, but neither of these have been confirmed so far in the books.