A query is broken up into terms and operators. There are three types of terms: Single Terms, Phrases, and Subqueries.
A Single Term is a single word such as "test" or "hello".
A Phrase is a group of words surrounded by double quotes such as "hello dolly".
A Subquery is a query surrounded by parentheses such as "(hello dolly)".
Multiple terms can be combined together with boolean operators to form complex queries (see below).