Tennis is a highly popular sport played individually against a single opponent (singles) or between two teams of two players each (doubles). It is played on a rectangular court with a net stretched across the center. The objective of the game is to score points by hitting a tennis ball over the net and into the opponent's court in such a way that they cannot return it properly.

Key features of tennis include:

1. Court: The court is divided into two halves by the net. Each half is further divided into service courts and a baseline. The dimensions of the court are standardized.

2. Scoring: Tennis uses a unique scoring system with points awarded in sets and games. Players start at "love" (0 points) and score progresses to 15, 30, 40, and then the game point. A player must win at least four points and have a two-point lead to win a game.

3. Equipment: Players use a tennis racket to hit a felt-covered rubber ball over the net. Rackets vary in size and weight, while balls come in different types for various playing surfaces.

4. Rules: Tennis has rules governing every aspect of play, from how to serve and return the ball to what constitutes a fault or let. Matches are usually best-of-three sets (women) or best-of-five sets (men) in major tournaments.

5. Technique: Players use a variety of strokes including the serve, forehand, backhand, volley, and overhead smash. Different surfaces (hard, grass, clay) affect play styles and strategies.

6. Professional Tennis: The sport has a rich history with major tournaments like Wimbledon, the US Open, French Open, and Australian Open being part of the Grand Slam circuit. Players compete for rankings, prize money, and prestige.

Tennis is known for its fast-paced action, skillful play, and mental toughness required from its players. It combines elements of strategy, athleticism, and precision, making it a widely loved sport worldwide.