Meaning of “hiss” - Learner’s Dictionary

hiss

verb uk us /hɪs/
MAKE NOISE [ I ]

to make a long noise like the letter 's':

The gas hissed through the pipes.
SPEAK [ T ]

to speak in an angry or urgent way:

"Will you be quiet," she hissed.
hiss noun [ C ]

a sound like the letter 's'

(Definition of “hiss” from the Cambridge Learner’s Dictionary © Cambridge University Press)