First, Teaspoon. The expression is one teaspoon of loose tea per cup, and one for the pot. For a single cup, one teaspoon. Thus teaspoon. A tablespoon is three teaspoons.
True colors (or colours). Naval war etiquette required taking down your false flag before initiating battle.
Learning the ropes. Sailing ships had over 300 ropes and lines. Newbies had to learn them all, on the double.