493bbc30__Touch_Gesture_Reference_Guide__Platform_Description
[Platform] iPhone OS [Platform Gesture] Touch and hold [Core Gesture] Press [Platform Description] 
A user gesture used to display an information bubble, magnify content under the finger, or to perform specificactions in built-in applications and features. To touch and hold, users touch the screen, leaving their finger motionless until the information is displayed or the action occurs.
LukeW | Touch Gesture Reference Guide
Platform Description