A temporary window presented to a user (usually as a small box)
Pop-up refers to a window or dialog box that is presented or called by another program or window.
Better divs login
"Generally a pop-up is a better option for a login dialog and a pop-up would allow you to easily navigate to the main page"
from question "Setting Flyout to Main Frame Navigation(Windows 8.1 app store)"
"Use floating divs instead which looks like a modal dialog but are better than the pop-up"
from question "Modal dialog options"
Box datebox panel
"Because of datebox pop-up z-index is less then your box mean dialog box s z-index it shows behind pop-up panel"
from question "Datepicker not visible on popupPanel"
"When typing in the text box the autocomplete pop-up but is bigger than the remaining space in the modal dialog"
from question "JQuery autocomplete box to flow out of SharePoint modal dialog"
Window bubble higher
"Dialog makes it easier for you to create a pop-up window with customized contents"
from question "Java JOptionPane custom draw on background"
"I realize this is an older post but we just ran into the same issue and resolved it by setting the z-index of the bubble pop-up to something higher than the dialog window"
from question "JQuery BubblePopup not displaying on modal dialog"
"From a practice standpoint - excluding accessibility - modal windows provide an alternative that are less startling as say dialog boxes and feel less intrusive than pop-up windows"
from question "Are modal dialogs a good practice for the web?"
"Feed dialog is more intrusive in the sense that it has a facebook pop-up window"
from question "Feed dialog vs explicit sharing"
"I am using jquery ui dialog to show more than one pop-up on one page each pop-up will have its own id and it will be triggered by an anchor with a attribute"
from question "Show UI dialogs using data-popup attributes"