10am, 3pm and 9pm were my teatimes when brought up on the croft ( a smallholding with animals like a mini farm). You also have the 3 main meals Breakfast, Dinner and Supper.
Teatime also can be a short break at work sometimes called a teabreak and the times will vary depending on your shift
Also "Teatime" often refers to main evening meal of the day and eaten anywhere between 4pm and 7pm and sometimes even later.
Lastly some call teatime the last snack of the day had around 8pm -10pm
the only meal that has a set name that doesn't chance seams to be breakfast the rest of the meals are called different things by different people, like lunch, dinner and supper or tea oh and also "brunch" is most commonly eaten at the weekend.