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.
With the spread of Islam, it acquired a meaning of "practical ethics" (rather than directly religious strictures) around the 8th century.
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".