Adab (Arabic: أدب) in the context of behavior, refers to prescribed Islamic etiquette: "refinement, good manners, morals, decorum, decency, humaneness".
Muslims refer to Adab as good manners, courtesy, respect, and appropriateness, covering acts such as entering or exiting a washroom, posture when sitting, and cleansing oneself.
The term simply meant "behavior" in pre-Islamic Arabia, although it included other norms and habits of conduct.
Among the lower strata of society, it acquired something of its modern meanings of civility, courtesy, manners, and decency.
The term became popular and used in many contexts; for example, in the 10th century, the Brethren of Purity (Ikhwān al-Ṣafā) devoted much text to their philosophical exploration of the adab, and Abu Hayyan al-Tawhidi wrote extensively on the topic.
Abu Ishaq al-Tha'labi also wrote extensively, drawing a program for society and human conduct in general in his work based on adab.
[18] and Ali ibn Husayn Zayn al-Abidin said:"It is your child's right to bring him up with good manners and morals".