attic

Also called: loft (US)

Standards

one, or a combination of, the following:

(a) Attic (decorative) A low storey or decorative parapet above the main cornice of a classical building, originally designed to hide the roof slope.
(b) Attic (storage) The accessible space within a sloping roof of a house, often used for storage.
(c) Attic (habitable) A habitable upper storey or room(s), built entirely within the roof space of a building, with stair access from the floor below and usually lit by dormers or skylights.

In the case of a multistorey dwelling, the ceiling means the ceiling of each storey of the building.

Source - AS/NZS 2918:2018: Installation

HB50

<space> space mainly contained within the space below a pitched roof that may or may not be habitable

In the US this space is not intended to be habitable and is often used for storage.