No, as I read it, a majority means more than 50% of all of the delegates awarded. Cruz got a plurality in Iowa, but not a majority. In other words, Cruz won 8, but all of the others combined won 24; therefore, Cruz did not win a majority. However, Trump did win a majority in South Carolina. In fact he won all of the delegates. Going forward, and especially with the winner take all states coming up, it’s hard to see Cruz picking up more than two other states, whereas Trump should easily exceed eight.
He also won a majority in NH