A section is a military unit in the British Army consisting of eight soldiers, including a Corporal as section commander, a Lance Corporal as second-in-command, and six privates. The section splits down into two fire teams of four, commanded by the Corporal and Lance Corporal. Three sections together form a platoon.
The Canadian Army also uses sections, which is roughly the same as it's British counterpart except it is lead by a Sergeant and a Master Corporal as 2nd in command.
A section is roughly equivalent to a squad in the US Army.