A girl who resorts to their own sex after many failed relationships with the opposite sex. Once an opportunity with a male arises again, they return, but if things go poorly, the process is repeated. Subject is usually very overtly bitchy, for lack of better word
1. Toby - "Dyke by necessity! Totally is, poor thing "
Zeus - "I feel bad for sending her back but what's a guy to do. She'll be back one day."
Peter- "Did I just hear someone say, dyke by necessity? did she go running back, wow third time in two months!"
2. Commonly mistaken for a bisexual, a dyke by necessity is an interesting specimen that only returns for comfort.