Chronograph watches can measure and display elapsed time. Usually three subcounters on the dial display the elapsed seconds, minutes and hours.
The date is a small window on the dial which indicates the day of the month (between 1 and 31).
A day date watch displays the days of the week (from monday to sunday) and the date (between 1 and 31).
Watches featuring a GMT complication (which stands for Greenwich Mean Time) can display a second time zone thanks to an additional hand. They are much appreciated by travelers and airline pilots.
Watches featuring an « alarm » can be set in advance to ring at a certain moment. These watches are often used to wake you up in the morning.