Two (Non-Classical) Riddles

What fact connects the following words?

cross, lane, return, rock, waltz

How about the following series of words and phrases?

amnesia, babe, baby, blues, crowd, gal, girls, hardwood floor, healin’, heart, husband, man, merry go round, moon, night time man, season, song, troubles, waltz, women

Too hard? If suffixes count, the second series also includes -in’ and -itis. And the two riddles are parallel: they have different answers, but work in much the same way. Answers may be placed in the comments. There is no prize but the honor of solving the puzzle. There may be another clue around here somewhere, too.