Page conditions, also referred to as page show & hide, are conditions that control whether a page in the survey will be shown to a respondent. The conditions are based on the respondent's answers for question in page preceding the page with the condition. An alternative to page conditions is skip logic.
Page conditions are accessed from tool Page Show & Hide in the Page detail screen.
For example, in a survey about smart phone usage, the first page might contain a question asking the respondent if they own a smart phone. Then, all subsequent pages in the survey would contain a condition requiring a positive answer to the question. If the respondent answered "No" to the question about ownership of a smart phone, they would not be asked for any further question.
For details on how to create a page condition see Conditions