For me, select box is a control with predefined list of options that can be shown and hidden in window-blinds style. Combo box is the same, but new entry can be

For me, select box is a control with predefined list of options that can be shown and hidden in window-blinds style. Combo box is the same, but new entry can be added by directly typing in the box. They look the same but have different behavior. Dropdown is any of those and thus defines only the visual aspect, not the behavior.