What term is used to describe a vocal technique that creates slight pitch variations?

Vibrato is the correct term used to describe a vocal technique that creates slight pitch variations. This technique involves oscillating the pitch of a note slightly above and below the fundamental frequency, which adds warmth and richness to the sound. It is widely used in various singing styles, as it enhances emotional expression and helps sustain notes.

In contrast, falsetto refers to a vocal register that occupies a range higher than the normal singing voice, often characterized by a light, airy sound. Glissando involves sliding from one pitch to another, creating a continuous pitch transition rather than slight variations around a single pitch. Portamento is similar to glissando but specifically refers to the smooth connection between two pitches, emphasizing the transition rather than the slight fluctuations around a note.