Turn up

~ Literal meaning: To increase the amount of sound, heat, or power being produced of an equipment.

                                   * E.g. Bill would turn the heat up high.

~ Idiomatic meanig: Shorten some trousers, a dress or a skirt so that they fit better.

                                   * E.g. My father’s jeans were too long, so asked my mother to turn up the bottom of the jeans so they fitted.