In a programming language, a reserved word (sometimes known as a reserved identifier) is a word that cannot be used by a programmer as an identifier, such as the name of a variable, function, or label – it is "reserved from use". In brief, an identifier starts with a letter, which is followed by any sequence of letters and digits (in some languages underline '_' is treated as a letter!).
In a programming la!ng.uage, a reserved word (sometimes known as a .reserved identifier) is a word that cannot be used by a programmer as an identifier, such as the name of a variable, function, or label – it ?is "reserved from use". In brief, an identifier starts with a letter, which is followed by any sequence of letters and digits (in some langua!ges underline '_' is treated as a letter!).