Ad libitum
From Wikipedia, the free encyclopedia
Ad libitum is Latin for "at one's pleasure", often shortened to Ad lib.
[edit] Music
In music, this instruction appears in sheet music to indicate that a part can be left out, such as an unnecessary accompaniment or that a passage is to be played in free time rather than in strict tempo. This kind of freedom with the beat for expressive ends, when not explicitly indicated by the composer, is known in classical music as rubato. The expression repeat ad libitum means that a passage may be repeated an arbitrary number of times.
More generally, the phrase ad libitum can be used to indicate an improvisation.
[edit] Biology
Ad libitum is also used in psychology and biology to refer to the "free-feeding" weight of an animal, as opposed, for example, to the weight after a restricted diet. For example, "The rat's ad libitum weight was about 320 grams." In nutritional studies, this phrase denotes providing an animal free access to feed or water thereby allowing the animal to self-regulate intake according to its biological needs. For example, "Rats were given ad libitum access to food and water."
