Translating 'Half'

The English word "half" can be translated to Spanish in several ways, depending, among other things, what part of speech it is used as.

Medio is used as an adjective, and as such it agrees with the noun it refers to in number and gender.

Examples: El edificio ocupa una media manzana. (The building occupies half a block.) Contiene sólo 103 calorías por media taza. (It has only 103 calories per half-cup.) Es medio hombre, medio vampiro. (He's half man, half vampire.) Pasaban las horas y las medias horas también. (The hours passed, and so did the half-hours.)

In some cases, the noun that medio (or one of its variations) refers to can be omitted:

Examples: Hay tres clases semanales de una hora y media. (There are three weekly classes of an hour and a half.) Necesito una cuchara y media de azúcar. (I need a spoonful and a half of sugar.)

Medio also is used as an adverb, usually referring to adjectives. In standard Spanish, it is invariable, not changing in number or gender with the adjective it refers to. (In some areas, it is not unusual in spoken Spanish to change the form of medio to agree with the adjective, but such use is considered substandard.)

Examples: ¿No será una de esas mujeres medio locas? (You wouldn't be one of those half-crazy women?) Siempre te veo medio borracho. (I always see you half-drunk.) La tarea está medio hecha. (The homework is half-done.)

A medias is a phrase that can be function as either an adjective or adverb.

Examples: Accesibilidad a medias no es accesibilidad. (Half-accessibility isn't accessibility.) Esa información contiene verdades a medias. (The information contains half-truths.) La mirilla me permite ver a medias la silueta. (The peephole lets me half-see the outline.) Comprendo a medias muchas canciones en inglés. (I half-understand many songs in English.)

La mitad, which often means "middle," can also be used as a noun to mean "half."

Examples: El vino rojo reduce a la mitad el riesgo. (Red wine reduces the risk to half.) Replantaramos la mitad del césped. (We will replant half the lawn.) Cada segundo se crea un blog nuevo, pero solo la mitad permanecen activos. (Each second a new blog is created, but only half remain active.) ¡Cartuchos de impresora a mitad de precio! (Printer cartridges at half price!)