n.1. A place at which or the means by which a crossing is made.
2. A short connecting track by which a train can be transferred from one line to another.
3. Genetics Crossing over.
4. A registered member of one political party who votes in the primary of the other party.
5. a. The adaptation of a musical style, as by blending elements of two or more styles or categories, to appeal to a wider audience.
b. One, such as a performer, song, or movie, that appeals to more than one segment of an audience or market.