What do the referee's commands mean in fencing?

• The sequence: "On guard!", then "Are you ready?", then "Play!".
• Still: fencers "must come on guard correctly and remain completely still until the command 'Play!'".
• Before play: "No movement made or initiated before the word 'Play!' is counted."
• Halt: after it "a competitor may not start a new action; only a movement which has been begun before the order was given remains valid".
• Stopping early: "If a competitor stops before the word 'Halt!', and is hit, the hit is valid."
• When halt is called: if play is dangerous, confused or against the rules, if a fencer is disarmed or leaves the piste, or when fencers are body to body.
• Distance: on guard, the two points must not be able to touch with both arms straight.
• Not in line: at foil and sabre a fencer may not come on guard with the arm straight and the point threatening.
• Who stands where: the fencer called first is on the referee's right, unless a left-hander is involved.
• The salute: before the bout, mask under the arm, guard raised to the chin and blade lowered.
• The mask: kept on until the referee calls "Halt!".
• Speaking to the referee: not until the referee has given the decision.

The glossary has the on guard entry, the referee, the fencer's salute, the bout and the hit.

Hits arrive in fractions of a second, so the rules have to fix exactly when fencing is live. A hit launched before "Halt!" still counts because a fencer cannot stop a lunge in mid-air, and a fencer who drops their guard before the word has only themselves to blame.