randomly vs serendipitously

randomly

adv
  • In a random manner. 

  • By random access; at any point at a given time; not sequentially. 

serendipitously

adv
  • By serendipity; by blind luck in combination with wisdom; by fortunate accident. 

How often have the words randomly and serendipitously occurred in a corpus of books? (source: Google Ngram Viewer )