"Users." Google replaced the term "unique visitors” with "users" on Apr. 16, 2014 and said the terms mean the same thing. "Unique visitors" (aka "users") are defined by Google Analytics as (as of June 27, 2013): "Unique Visitors represents the number of unduplicated (counted only once) visitors to your website over the course of a specified time period. A Unique Visitor is determined using cookies." ProCon.org determines unique visitors each month then adds all the monthly data together for the year's total.
"Pageviews" are defined by Google Analytics as (as of Jan. 19, 2018): "Pageviews is the total number of pages viewed. Repeated views of a single page are counted."