What does disjunct mean?

Question

I am trying to understand the definition of a disjunctive normal form. I got this definition from this textbook:

A propositional formula is in disjunctive normal form if it consists of a disjunction of $(1, … ,n)$ disjuncts where each disjunct consists of a conjunction of $(1, …, m)$ atomic formulas or the negation of an atomic formula. Example of what is and what not is a disjunctive normal form:

• Yes $(p∧¬q)∨(¬q∨q)$
• No $p∧(p∨q)$

I do not know what a disjunct is, so I searched on Google and found that, according to Google, a disjunct is each of the terms of a disjunctive proposition.

So, I got a new question from this definition of disjunct. What do the terms of a disjunctive proposition refer to? Specifically, what is the meaning of terms in this context?

Answer 1

1. A disjunct of a disjunction is simply one its two inputs. So, $$P\lor Q$$ has disjuncts $P$ and $Q.$

2. The compound disjunction $$P\lor Q\lor R\lor S$$ can be considered to have four disjuncts, $P,Q,R$ and $S.$ However, someone literal-minded might argue that it has six distinct disjuncts, including either $(P\lor Q)$ or $(R\lor S),$ depending on whether the sentence is read left-to-right or right-to-left.

3. We do not speak of the "disjuncts" of a sentence like $$P\lor Q\lor R\land S\lor T,$$ because.... confusing.