That is the symbol for an enhancement-mode N-channel MOSFET. The most common NFets require 10V Gate-to-Source to turn on fully. They begin turning on with a Vgs of 3.5 to 5V, but do not produce their advertised On-resistance until Vgs gets to 10V.
There are a few special FETs that turn-on fully with only 5Vgs. You have to look up the data sheets to check the specs for any given FET.
They are called logic level MOSFET's, and they are quite common. Then there are some less common devices like the Si1032R/X which are on at 1.8V, or somewhere around there.