Vibrato is a musical technique used when singing or playing an instrument, where a slight variation in pitch is produced. It creates a wobbling or pulsating effect, which adds expression and emotion to the sound. Full definition
For example, waggling the finger on a key creates the sound of vibrato, often heard from a violin. (newscientist.com)
«We were very excited to find that distantly related mammal species appear to produce calls with vibrato - like pitch modulation in order to improve the perception of important information encoded by formants,» Charlton says. (sciencedaily.com)
Like the Seaboard Rise, the apps 3D Touch feature allows users to shift the pitch by pressing harder, or create vibrato with just a finger wiggle, however, you'll need to be using the app on a newer iPhone with 3D Touch to utilize these attributes. (knowtechie.com)