When you overhear only a small bit of information, this is an example of a snippet of information.
From the snippet I heard of their rehearsal, they sound pretty good.
The key is to literally just take off a little bit; even a snippet will do.
A movie trailer is a short preview or a snippet of a film that is meant to get viewers excited to the see the film when it is released.
Arias, soliloquies and an occasional snippet of poetry punctuate your servers' recitation of the evening specials.
You can't give us that tantalizing snippet of info only to leave us hanging.