Sentence:  But it wasn't until [Theresa M. Claiborne] went to ROTC training camp at the University of California at Berkeley that she discovered that flying was her first <WSD>love</WSD>. "Pilots talk about getting bit by the flying bug," she says. "I thought, This is heaven." 
Meaning of the word marked with <WSD> tags:  A thing, activity(,) etc which is the object of one's deep liking or enthusiasm.