In short: sīla means ethics: living without harming, usually through the five precepts. The Buddha said: "Mendicants, an ethical person, who has fulfilled ethical conduct, need not make a wish: 'May I have no regrets!' It's only natural that an ethical person has no regrets" (AN 10.2).
✦ What it leads to
No regret → joy → calm → happiness → a still mind → clear seeing. (AN 10.2)
☸ In practice
The five precepts · Precepts as gifts · Right action · Right speech
Questions people ask
What does sila mean?
Sīla means ethics or virtue, usually practiced as the five precepts. The Buddha taught that it leads naturally to freedom from regret, joy and calm (AN 10.2).