In computer programming, a declaration determines the name and data type of a variable or other element. Programmers declare variables by writing the name of the variable into code, along with any data type indicators and other required syntax.
Techopedia explains Declaration
A declaration in computer programming can be confused with other sorts of designations for variables. One such term is the definition of a variable, which refers to assigning a storage location for that variable. Another similar term is dimensioning variables, which refers to reserving memory for the variables by determining the length or size of variables. Programmers commonly dimension variables and arrays to help the program handle elements of a specific size.
The use of various syntax and protocols for declaring variables in different programming languages can lead to some confusion. Flexibility written into some coding languages can result in glitches or bugs that can be hard to fix. Programmers can use resources like the "explicit" option in some programming languages to create more specific parameters for declaring variables.