The user experience (of a product or service) manifests through three aspects: the user interface (UI), the information architecture (IA) and the presentation design (PD).

UX User Experience

UI
User Interface

IA
Information Architecture

PD
Presentation Design

MeansContentPresentation
To access the service or functionality.Everything that has informational value inherent in the service or product.The look; manifested within the UI and IA frameworks.
Buttons, sliders, gestures, textures …Reading hierarchy, headings, taxonomy…Colours, typography, sounds, branding guidelines…

Here are some examples.

UI

IA

PD

ServiceCustomer service procedures.Structure of forms and pamphlets.Graphic design.
Physical ProductButtons, dials, materials, and textures.Structure of instructions, labels and manuals.Graphic and product design.
ApplicationButtons, sliders, and gestures.Structure of screens and forms.Graphic and multimedia design.

In practice, activities blur across these tidy boundaries of course.