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1.
When two friends verbally agree they are besties aka best friends, bff's, etc.
Karen & Kate made their bestiship official and put an end to the chain of unrequited besties.
by crrrl February 11, 2009
 
2.
The fact of being besties
My bestiship with Lydia used to be something I had renounced to, but latest events proved that it was stronger than ever.
by MeliorMelusine June 05, 2011