Sick leave refers to a time period in which a person does not come to work so that they can deal with an illness or temporary disability. Sometimes, companies will keep paying employees for these days off, and sometimes they do not.
In the context of the law, many employment contracts allow a certain amount of days for sick leave.
Legal issues can arise if an employer tries to punish an employee for taking days off for sick leave. For example, if an employee is fired due to taking days off for sick leave, that person may sue the company for wrongful termination. In such a case, the exact terms of the employment contract would come into play. Many employment contracts will give employees a certain amount of sick days, e.g., 7–10 days a year.