pica

Most often, this word refers to a condition where a person keeps craving and eating things that are not food. That can mean dirt, clay, ice, paper, or other items with no real food value. It is not the same as simple curiosity or a one-time dare. When it continues, it can cause real health problems.

It is sometimes linked to iron or zinc deficiency, pregnancy, or certain developmental or mental health conditions. In a very different field, the word is also used in printing and typography, where it names a unit of measure equal to 12 points.

Most commonly, pica refers to an eating disorder in which someone repeatedly craves and eats things that are not food and have little or no nutritional value. These may include dirt, clay, chalk, ice, paper, hair, metal, stones, or similar substances. It is more than a strange habit or a one-time impulse. When the behavior continues, it can lead to poisoning, dental damage, stomach or bowel problems, and other serious health risks.

The causes are not always simple. It can appear alongside iron or zinc deficiency, pregnancy, early childhood, or some developmental or mental health conditions. In medical use, the behavior usually has to last for at least a month and be inappropriate for the person's developmental stage. It also should not be part of a normal cultural practice. Treatment often focuses on the cause, such as correcting a deficiency or giving behavioral or medical support.

The word also has a separate meaning in printing, publishing, and typography. There, a pica is a unit used to measure type and page layout. In modern typography, one pica equals 12 points, and printers have long used it to describe line width, spacing, and type size. You may also see the term used for a type size of 12 points.

So in everyday English, the medical meaning is usually the one people mean. But in design or printing contexts, the word often points to measurement rather than health.