noun.the ability to find valuable or agreeable things not sought for; also: luck that takes the form of such finding

• … materials researchers, who now rely mostly on rules of thumb, trial-and-error and serendipity for developing new materials.
• As they leapfrog from South Africa to Singapore in search of local delicacies, the authors prove again and again that serendipity is the traveler's strongest ally: many of their most memorable meals issue from the hands of generous strangers …