1.1 Macule

Macule, patch

A flat, non-palpable, localized change in color of skin. Usually sharp borders
If larger than 1 cm: patch
Colors: red, brown, black, white, blue, yellow
Size: several millimeters 

Petechia (punctate bleeding into skin), purpura (small areas of bleeding), hematoma (larger areas of bleeding), deposition of pigmented material of different origin

Can appear anywhere on skin; for example macular exanthem
On mucosa: enanthem

May develop into hive or a papule
May over time develop additional scaling 
Often associated with papules, vesicles and pustules

Large red patch = erythema
Erythroderma (generalized redness, often infiltrated)
Flush (acute transient facial erythema)

Drug induced eruption, macular lentigo, viral exanthema, vitiligo, pytiriasis versicolor

Vascular dilation, either because of aberrant vessels or inflammatory mediators (red): endogenous or exogenous pigment, for example melanin (brown-black, blue-gray), hemoglobulin (red-blue), hemosiderin (brown) lipids (yellow), loss of pigment (white) , external deposition of foreign body material (trauma, tattoo)