Ad Libitum: Origin And Meanings

The term ad libitum is a Latin expression that means “at will” or “at will”, and it is usual to observe its abbreviation “ad lib.” in different texts that range from theater scripts, medical prescriptions, to the world of politics. 

On some occasions, this term is often confused with “a piacere”, which is Italian and also means “at ease”, but generally this confusion occurs only in the world of music, something that we will see later.

Origin of the term

Describing the origin of the term ad libitum is equivalent to going back to the origins of the Latin language, a language spoken during Ancient Rome (8th century BC) and later during the Middle Ages and Modern Ages , remaining after the Contemporary Age as a scientific language until the century XIX.

That is why we see it written in such different branches but that at the same time have their bases in very past times, such as music, medicine or law.

Today it is practically not used, much less in the everyday language of the so-called “Romance languages” (such as Spanish, French or Italian, among others), those that derived from “Vulgar Latin”, that is, the one commonly spoken.


The areas where the term “ad libitum” or its narrow version “ad lib” is used. they are many. They range from the world of music to that of fashion or politics, and in the vast majority of cases it means the same thing, but adapting to each context. Let’s see:

In music

If you read a sheet music or part and you come across the term ad libitum it means “at will”. But be careful: it can have different meanings:

– In the performance of a passage in a free rhythm instead of its own tempo. When this practice is not explicitly indicated by the composer, it is known as “rubato”, which always affects the tempos, never the notes.

– When improvising a melodic line that conforms to the general platform constituted by the notes or chords written in the passage.

– When used to bypass an instrumental part, such as an accompaniment that is not required, for the duration of the passage. This indication is the opposite of “obbligato”. 

– When the phrase “repeat ad libtium” appears, to play the passage an arbitrary number of times.

– In other cases the term may arise to indicate that a piece of music can be interpreted with or without the indicated instrument. This can be the case of “harmonica, ad libitum” or “harmonica ad.lib”. 

As we said at the beginning of the article, ad libtium is often confused with “a piacere”, mostly in the musical field. The latter has a more specific meaning, usually in reference only to the first two types of criteria that we mentioned at the beginning of this list.

For its part, baroque music has an ad libitum or “ad lib.” written or implicit, with which many composers refer to the freedom of the performer and the conductor.

Meanwhile, jazz or classical music after the baroque style have a different term, called “cadenza.”

In fashion

There is an «adlib» concept, and it has its origin in Spain, more precisely in Ibiza. It was created in the 1970s, with a strong influence from the hippie movement and inspired by the dresses that were used to be worn in the Pitiusas Islands (two Mediterranean islands, one of them Ibiza and the other, Formentera).

This indigenous style of dress consists of light dresses in light colors, white being the most common, an ideal combination to cope with the extreme heat that is in that area during the summer.

It captivated thousands of tourists, as well as the Serbian princess Smila Mihailovich, who was in charge of promoting this way of dressing “adlib” all over the world. Thus, this “look” gives prominence to the body itself with elegance, freedom and comfort.

Some of the exponents of adlib fashion are Pepa Bonett, Charo Ruiz, Tony Bonet, Ibi Moda and Piluca Bayarri, among others.

In the theatrical world

When the term “ad lib” is read in a theater, film or television novel script, it means that the actors must improvise at that moment, such as a dialogue.

In medicine

Surely this is the field that you read the most times to this term, but that you ignored. It is present for example in the leaflets of the remedies that you buy in the pharmacy. In this case, the term “ad lib” means that the administration of the drug will depend on the will of the patient.

In biology

Its use in this branch is very punctual, and it occurs when you want to indicate the weight of an animal when no diet has yet been indicated. That is, “the weight of the mouse ad libitum was 296 grams.”

But be careful: in biology it can also have another meaning, since in field studies it can mean that certain information was obtained spontaneously without a specific method.

On the other hand, when nutritional studies are carried out, it is common for an animal to have access at the discretion of an animal to drink water or eat food in order to let the biological needs that govern the feeding of such a specimen. In such cases it will be said: “the mouse was given ad libitum access to food and water.”

In politics

The term “ad libitum” is usually written in the drafting of presidential decrees, which differ from laws by not passing through the different chambers that make up the legislative power. In other words, a decree is something that the president orders because he wishes or considers it so.

In the Catholic liturgy

Let’s start from the base defining the Catholic liturgy as the set of actions with which God is worshiped. In that sense, the ad libitum is used when referring to a religious festival, or the celebration of the memory of a saint belonging to the Catholic saints.

In legal law

The term is generally used as an address that imparts a license to alter or omit a part. The abbreviated version “ad lib.” Is generally used, which means “at the pleasure of the performers.”

So we are talking about acquired property rights, which for example cannot be eliminated ad libitum by retrospective legislation.


  1. APARTE – Action for the Theater. (2011). Recovered from:
  2. Paul Rees. (2013). “Dictionary of Zoo Biology and Animal Management . Recovered from:
  3. Adlib (2019). Ibiza fashion. Recovered from:
  4. Christine Anmer (2017). “The Facts on File Dictionary of Music . Recovered from:
  5. USLegal (2016). Recovered from:

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