antecedent

A basic principle of clear writing is to keep your antecedents clear. Pronouns are often used in order not to repeat a noun (so instead of saying "Sheila turns 22 tomorrow, and Sheila is having a party", we replace the second "Sheila" with "she"). But sloppy writers sometimes leave their antecedents unclear (for instance, "Sheila helps Kathleen out, but she doesn't appreciate it", where it isn't clear who "she" is). Watch out for this possible problem when using not just he and she but also they, them, it, this, *and *that. And keep in mind that antecedent isn't just a grammar term. You may talk about the antecedents of heart disease (such as bad eating habits), the antecedents of World War II (such as the unwise Treaty of Versailles), and even your own antecedents (your mother, grandfather, etc.).