Definition - What does Spinner mean?
A spinner is a graphical GUI widget that allows a user to modify the value in the adjacent text box by either clicking the up or down arrow, or holding the up or down arrow, thereby allowing the value to increase or decrease. If a user holds down the up arrow, then the text box value increases. If a user holds down the down arrow, the text box value decreases. The speed of the value change may increase as the button is held down.
Functionally, spinners are much like scrollbars, sliders, combo boxes or lists, but they are considered beneficial because they do not change the visible display or cover up other values on a screen.
A spinner is also known as a spinbox or spinner control.
Techopedia explains Spinner
In most cases, a spinner value is displayed in the text box adjacent to the spinner. This allows users to make use of the spinner to modify the value, or enter the value directly into the text box.
Spinners are used for numbers, months of the year, countries and other common values. Spinners are most useful when users do not need to see the whole range of values in order to make a selection.