Tuples

A tuple is a list of values. Many methods and callbacks in the Roblox Engine API accept and return multiple values, but the API Reference says "Tuple" instead of those values.

Parameters

If a method or callback accepts a tuple as a parameter, then it accepts multiple values. For example, the API Reference shows that the BindableFunction:Invoke() method accepts a "Tuple" as a parameter, so it accepts multiple arguments.

BindableFunction:Invoke(1, true, "string", Vector3.new(0, 0, 0))

Returns

If a method or callback returns a tuple, then it returns multiple values. For example, the API Reference shows that the Players:GetUserThumbnailAsync() method returns a "Tuple", so it returns multiple values. The first return value is a Content URL, and the second is a boolean.

local Players = game:GetService("Players")

local userId = 156 -- builderman
local thumbType = Enum.ThumbnailType.HeadShot
local thumbSize = Enum.ThumbnailSize.Size420x420
local content, isReady = Players:GetUserThumbnailAsync(userId, thumbType, thumbSize)
print(content, isReady) -- rbxthumb://type=AvatarHeadShot&id=156&w=420&h=420 true