Our Glossary of Usage contains 70 sets of commonly confused words. Of course you know the difference between such similar-sounding words as affect and effect, conscience and conscious, lightening and lightning. So why can't anybody else keep them straight?

These six sets of commonly confused words may provide some clues.

• Aggravate & Irritate
  The verb aggravate means "to make a bad condition worse." But it's also commonly used as a synonym for irritate--"annoy," "bother," or "make angry." Is this common usage correct? That depends on which authority you listen to.


• Baited & Bated
  A hook, witness, or animal can be baited ("lured, enticed, tempted"). But if your breath is baited, something has gone terribly wrong.


• Farther & Further
  Farther usually refers to physical distance. Further refers to an extension of time or degree. Usually.


• Its & It's
  The apostrophe signals possession, right? But not with it's.


• Principal & Principle
  Sure, the principal is our pal. But what's the principal definition of this word?


• Who & Whom
  Though whom may sound as old fashioned as 23 skidoo, it still has a role (or is it roll?) to play.

More About Words:

• The Earliest English Dictionaries
• Common Redundancies
• Common Errors and How to Fix Them