The phrase "main thrust" means the most important or central point or objective of something. It refers to the key focus or direction that a person, plan, or project is pursuing. Full definition
He's talking about restaurants in New York City that don't necessarily specialize in fish, where the «main thrust of their business» isn't seafood, Bourdain wrote in his more recent book, «Medium Raw.» (businessinsider.com)
Hoot follows the same path as another recently successful family film, Holes, in its themes and main thrust in terms of how it plays to its target audience. (qwipster.net)
Two years ago, I heard a Christmas sermon whose main thrust was the importance of paying bills on time. (religion-online.org)